Transparent electrode, solar cell, multi-junction solar cell, solar cell module, and photovoltaic power generation system

Abstract

A transparent electrode according to an embodiment is mainly composed of a compound containing elements represented by Zn, O, and M0, and the element represented by M0 is dispersed in the compound containing the elements represented by Zn, O, and M0 in a thickness direction with a sparse density distribution.

Description

Transparent electrodes, solar cells, multi-junction solar cells, solar cell modules, and photovoltaic power generation systems

[0001] The present invention relates to a transparent electrode, a solar cell, a multi-junction solar cell, a solar cell module, and a solar power generation system.

[0002] One of the new solar cells is cuprous oxide (Cu ２ There are solar cells that use Cu as the light absorption layer. ２ O is a wide-gap semiconductor. Cu ２ O is a safe and inexpensive material made from copper and oxygen, which are abundant on Earth, and is therefore expected to enable the realization of highly efficient, low-cost solar cells.

[0003] YS Lee et al., Adv. Mater. 26 (2014) 4704.

[0004] The problem to be solved by the present invention is to provide a transparent electrode having low resistance.

[0005] The transparent electrode of the embodiment is mainly composed of a compound containing elements represented by Zn, O, and M0, and the element represented by M0 is dispersed in the compound containing the elements represented by Zn, O, and M0 with a sparse / dense distribution in the thickness direction.

[0006] FIG. 1 is a schematic cross-sectional view of a transparent electrode according to an embodiment. FIG. 2 is a diagram illustrating an analysis spot of a transparent electrode according to an embodiment. FIG. 3 is a graph showing the concentration of an element represented by M0 in the thickness direction of a transparent electrode at an analysis spot according to an embodiment. FIG. 4 is a schematic cross-sectional view of a solar cell according to an embodiment. FIG. 5 is a cross-sectional view of a multi-junction solar cell according to an embodiment. FIG. 6 is a perspective view of a solar cell module according to an embodiment. FIG. 7 is a cross-sectional view of a solar cell module according to an embodiment. FIG. 8 is a configuration diagram of a solar power generation system according to an embodiment. FIG. 10 is a schematic view of a vehicle according to an embodiment. FIG. 10 is a schematic view of a flying object according to an embodiment. FIG. 11 is a schematic view of a display device according to an embodiment. FIG. 12 is a table relating to examples. FIG. 13 is a table relating to examples. FIG. 14 is a table relating to examples. FIG. 15 is a table relating to examples.

[0007] A preferred embodiment of the present invention will be described in detail below with reference to the drawings. Unless otherwise specified, the physical property values ​​are those at 25°C and 1 atmosphere (atmosphere). Furthermore, the average indicates an arithmetic mean value. Unless otherwise specified, each concentration is the average concentration of the target region or layer. In each layer, a specific element is contained if, for example, the presence of the element is confirmed by SIMS (Secondary Ion Mass Spectrometry), and a specific element is not contained if, for example, the presence of the element cannot be confirmed by SIMS (an element below the detection limit).

[0008] In the specification, " / " represents a division symbol. However, the " / " in "or / and" means "or." In the specification, "・" represents a multiplication symbol. In the numerical values ​​in the specification, "." represents a decimal point.

[0009] (First Embodiment) The first embodiment relates to a transparent electrode. Fig. 1 shows a schematic cross-sectional view of a transparent electrode. The transparent electrode 10 shown in the schematic cross-sectional view of Fig. 1 is mainly composed of a compound containing elements represented by Zn, O, and M0. Fig. 1 is a cross-sectional view of the transparent electrode 10 in the thickness direction. The transparent electrode 10 is a conductive film that transmits light ranging from infrared light to visible light. The Z direction is the thickness direction of the transparent electrode 10, and the direction formed by the XY plane is the surface direction of the transparent electrode 10.

[0010] The thickness of the transparent electrode 10 is preferably 30 nm to 150 nm, more preferably 30 nm to 100 nm, and even more preferably 30 nm to 50 nm. The thickness of the transparent electrode 10 can be determined by cross-sectional observation using an electron microscope or a step gauge.

[0011] The compound containing elements represented by Zn, O, and M0 is mainly composed of elements represented by Zn, O, and M0. Preferably, 95 wt% to 100 wt% of the transparent electrode 10 is a compound containing elements represented by Zn, O, and M0, more preferably 98 wt% to 100 wt% is a compound containing elements represented by Zn, O, and M0, and even more preferably 99 wt% to 100 wt% is a compound containing elements represented by Zn, O, and M0. 100 wt% of the transparent electrode 10 can be composed of a compound containing elements represented by Zn, O, and M0.

[0012] In the compound containing Zn, O, and an element represented by M0, the element represented by M0 is preferably one or more elements selected from the group consisting of Al, B, and Ga. The element represented by M0 is preferably one element selected from the group consisting of Al, B, and Ga. The element represented by M0 is more preferably Al. The element represented by M0 is preferably B. The element represented by M0 is preferably Ga.

[0013] When the total of all elements contained in the compound containing the elements represented by Zn, O, and M0 is 100 [atom%], the total ratio of the elements represented by Zn, O, and M0 contained in the compound containing the elements represented by Zn, O, and M0 is preferably 95 [atom%] or more and 100 [atom%] or less, more preferably 98 [atom%] or more and 100 [atom%] or less, and even more preferably 99 [atom%] or more and 100 [atom%] or less. Note that the ratio of the elements contained in the compound containing the elements represented by Zn, O, and M0 can be determined by analysis using SIMS (Secondary Ion Mass Spectrometry).

[0014] The element represented by M0 is preferably dispersed with a density distribution in the thickness direction of the transparent electrode 10 in the compound containing the elements represented by Zn, O, and M0. The element represented by M0 is preferably dispersed with a density distribution in the thickness direction and / or plane direction of the transparent electrode 10 in the compound containing the elements represented by Zn, O, and M0. In other words, the element represented by M0 in the transparent electrode 10 is not uniformly dispersed in the compound containing the elements represented by Zn, O, and M0, and the concentration does not have a gradient in one direction. The element represented by M0 being dispersed with a density distribution preferably improves the transparency of the transparent electrode 10. By analyzing a cross section of the transparent electrode 10 using SEM-EDX (Scanning Electron Microscope-Energy Dispersive X-ray Spectrometry) or STEM-EDX (Scanning Transmission Electron Microscope-Energy Dispersive X-ray Spectrometry), it can be confirmed that the element represented by M0 is dispersed with a density distribution in the compound containing the elements represented by Zn, O, and M0.

[0015] The element represented by M0 is preferably anisotropically dispersed in the thickness direction of the transparent electrode 10 in the compound containing the elements represented by Zn, O, and M0. The element represented by M0 is preferably anisotropically dispersed in the thickness direction and / or plane direction of the transparent electrode 10 in the compound containing the elements represented by Zn, O, and M0. In other words, the element represented by M0 in the transparent electrode 10 is not uniformly dispersed in the compound containing the elements represented by Zn, O, and M0, and the concentration does not have a gradient in one direction. The anisotropically dispersed presence of the element represented by M0 preferably improves the transparency of the transparent electrode 10. Line analysis of the cross section of the transparent electrode 10 using SEM-EDX or STEM-EDX confirms that the element represented by M0 is anisotropically dispersed in the compound containing the elements represented by Zn, O, and M0.

[0016] The transparent electrode 10 preferably has a first region R1 having a high ratio of the element represented by M0 and a second region P1 having a low ratio of the element represented by M0 alternately repeated at least twice in the thickness direction. The transparent electrode 10 preferably has a first region R1 having a high ratio of the element represented by M0 and a second region P1 having a low ratio of the element represented by M0 alternately repeated at least twice in the thickness direction in the compound containing Zn, O, and M0. In other words, the element represented by M0 in the transparent electrode 10 is not uniformly dispersed in the compound containing Zn, O, and M0, and the concentration does not have a gradient in one direction. The thickness direction of the transparent electrode 10 is the distance between the principal surface, which is the surface with the largest area of ​​the transparent electrode 10, and the surface located opposite the principal surface.

[0017] The compound containing Zn, O, and elements represented by M0 preferably contains N in addition to the elements represented by Zn, O, and M0. The compound containing Zn, O, and elements represented by M0 preferably contains one or more elements selected from the group consisting of N, C, and H in addition to the elements represented by Zn, O, and M0. The compound containing Zn, O, and elements represented by M0 preferably contains N, C, and H in addition to the elements represented by Zn, O, and M0.

[0018] The inclusion of an element represented by M0 improves the light transmittance. Furthermore, when the element represented by M0 is present in a large amount, the resistance of the transparent electrode 10 is likely to increase. Therefore, it is preferable that the element represented by M0 occupies 1 atom % or more and 10 atom % or less in the transparent electrode 10, more preferably 2 atom % or more and 8 atom % or less in the transparent electrode 10, and even more preferably 3 atom % or more and 6 atom % or less in the transparent electrode 10.

[0019] When the total of all elements contained in a compound containing elements represented by Zn, O, and M0 is taken as 100 [atom %], the total ratio of elements represented by Zn, O, N, C, H, and M0 contained in a compound containing elements represented by Zn, O, and M0 is preferably 95 [atom %] or more and 100 [atom %] or less, more preferably 98 [atom %] or more and 100 [atom %] or less, and even more preferably 99 [atom %] or more and 100 [atom %] or less. This can be determined by SIMS analysis.

[0020] In a compound containing an element represented by Zn, O, and M0, it is preferable that the relationship Zn:M0:O:N:H:C=u1:v1:w1:x1:y1:z1 be satisfied, and that u1+v1+w1+x1+y1+z1=2, 0.95≦(u1+v1)≦1.15, u1>0, and v1>0 be satisfied.

[0021] In a compound containing an element represented by Zn, O, and M0, it is preferable that the relationship Zn:M0:O:N:H:C=u1:v1:w1:x1:y1:z1 be satisfied, and that the following conditions be satisfied: 0.91≦u1≦1.09, 0.009≦v1≦0.11, 0.86≦w1≦1.04, 0.00015≦x1≦0.0002, 0.0015≦y1≦0.002, 0.00015≦z1≦0.0002, 0.95≦(u1+v1)≦1.15, and 0.0019≦(x1+y1+z1)≦0.0022.

[0022] In a compound containing an element represented by Zn, O, and M0, it is more preferable that the relationship Zn:M0:O:N:H:C=u1:v1:w1:x1:y1:z1 be satisfied, and that the following conditions be satisfied: 0.92≦u1≦1.08, 0.018≦v1≦0.085, 0.87≦w1≦1.04, 0.00016≦x1≦0.00018, 0.0016≦y1≦0.0018, 0.00016≦z1≦0.00018, 0.97≦(u1+v1)≦1.13, and 0.002≦(x1+y1+z1)≦0.00215.

[0023] In a compound containing an element represented by Zn, O, and M0, it is even more preferable that the relationship Zn:M0:O:N:H:C=u1:v1:w1:x1:y1:z1 be satisfied, and that 0.93≦u1≦1.08, 0.025≦v1≦0.065, 0.88≦w1≦1.03, 0.00016≦x1≦0.00018, 0.0016≦y1≦0.0018, 0.00016≦z1≦0.00018, 0.99≦(u1+v1)≦1.1, and 0.002≦(x1+y1+z1)≦0.0021 be satisfied.

[0024] The compound containing Zn, O and elements represented by M0 is Zn ｕ２ M0 ｖ２ O ｗ２ N ｘ２ H ｙ２C ｚ２ Compounds represented by the formula: Zn ｕ２ M0 ｖ２ O ｗ２ N ｘ２ H ｙ２ C ｚ２ u2, v2, w2, x2, y2 and z2 of the compound represented by the formula: ｕ２ M0 ｖ２ O ｗ２ N ｘ２ H ｙ２ C ｚ２ It is preferable that u2, v2, w2, x2, y2, and z2 satisfy the following relationships: u2+v2+w2+x2+y2+z2=2, 0.95≦(u2+v2)≦1.15, u2>0, and v2>0.

[0025] Zn ｕ２ M0 ｖ２ O ｗ２ N ｘ２ H ｙ２ C ｚ２ In the compound represented by the formula (I), it is preferable that 0.91≦u2≦1.09, 0.009≦v2≦0.11, 0.86≦w2≦1.04, 0.00015≦x2≦0.0002, 0.0015≦y2≦0.002, 0.00015≦z2≦0.0002, 0.95≦(u2+v2)≦1.15, and 0.0019≦(x2+y2+z2)≦0.0022 are satisfied.

[0026] Zn ｕ２ M0 ｖ２ O ｗ２ N ｘ２ H ｙ２ C ｚ２ In the compound represented by the formula (I), it is more preferable that 0.92≦u2≦1.08, 0.018≦v2≦0.085, 0.87≦w2≦1.04, 0.00016≦x2≦0.00018, 0.0016≦y2≦0.0018, 0.00016≦z2≦0.00018, 0.97≦(u2+v2)≦1.13, and 0.002≦(x2+y2+z2)≦0.00215 are satisfied.

[0027] Zn ｕ２ M0 ｖ２ O ｗ２ N ｘ２ H ｙ２ C ｚ２In the compound represented by the formula (I), it is even more preferable that 0.93≦u2≦1.08, 0.025≦v2≦0.065, 0.88≦w2≦1.03, 0.00016≦x2≦0.00018, 0.0016≦y2≦0.0018, 0.00016≦z2≦0.00018, 0.99≦(u2+v2)≦1.1, and 0.002≦(x2+y2+z2)≦0.0021 are satisfied.

[0028] ZnO doped with an element represented by M0 is used as a transparent electrode having electrical conductivity. The element represented by M0 is preferably distributed anisotropically in the thickness direction of the transparent electrode 10. From the viewpoint of obtaining a low-resistance transparent electrode 10, it is preferable that a first region R1 having a high ratio of the element represented by M0 and a second region P1 having a low ratio of the element represented by M0 are alternately and repeatedly present.

[0029] It is believed that the element represented by M0 bonds more strongly with O than with Zn, inducing oxygen deficiency, thereby generating carriers. From the viewpoint of improving the conductivity of the transparent electrode 10, it is preferable that the element represented by M0 be distributed anisotropically in the thickness direction of the transparent electrode 10, rather than being uniformly dispersed in the thickness direction of the transparent electrode 10 or having a simple gradient change in the thickness direction of the transparent electrode 10.

[0030] It is preferable that the first region R1 having a high ratio of the element represented by M0 and the second region P1 having a low ratio of the element represented by M0 are alternately repeated two or more times in the thickness direction of the transparent electrode 10. The range in which the first region R1 having a high ratio of the element represented by M0 and the second region P1 having a low ratio of the element represented by M0 are alternately repeated two or more times in the thickness direction of the transparent electrode 10 is preferably 80% to 100% of the thickness of the transparent electrode 10. It is preferable that the first region R1 having a high ratio of the element represented by M0 and the second region P1 having a low ratio of the element represented by M0 are alternately repeated throughout the thickness direction of the transparent electrode 10.

[0031] It is preferable that 3 atom % or more and 10 atom % or less in the first region R1 are elements represented by M0, it is more preferable that 4 atom % or more and 8 atom % or less are elements represented by M0, and it is even more preferable that 5 atom % or more and 7 atom % or less are elements represented by M0.

[0032] It is preferable that 1 atom % or more and 8 atom % or less in the second region P1 are elements represented by M0, it is more preferable that 2 atom % or more and 6 atom % or less are elements represented by M0, and it is even more preferable that 3 atom % or more and 5 atom % or less are elements represented by M0.

[0033] In the first region R1 where the ratio of the element represented by M0 is high, the relationship is Zn:M0:O:N:H:C = u3:v3:w3:x3:y3:z3, and in the second region P1 where the ratio of the element represented by M0 is low, the relationship is Zn:M0:O:N:H:C = u4:v4:w4:x4:y4:z4.

[0034] In the first region R1 where the ratio of the element represented by M0 is high, the relationship is Zn:M0:O:N:H:C = u3:v3:w3:x3:y3:z3, and u3 + v3 + w3 + x3 + y3 + z3 = 2 is satisfied. In the second region P1 where the ratio of the element represented by M0 is low, the relationship is Zn:M0:O:N:H:C = u4:v4:w4:x4:y4:z4, and u4 + v4 + w4 + x4 + y4 + z4 = 2 is satisfied. u3 is preferably 0.971 to 0.995 times u4, more preferably 0.981 to 0.995 times u4, and even more preferably 0.985 to 0.990 times u4. Furthermore, v3 is preferably 1.194 to 3.885 times v4, more preferably 1.244 to 2.942 times v4, and even more preferably 1.485 to 1.971 times v4. Furthermore, w3 is preferably 0.971 to 0.995 times w4. Furthermore, x3 is preferably 0.971 to 0.995 times x4. Furthermore, y3 is preferably 0.971 to 0.995 times y4. Furthermore, z3 is preferably 0.971 to 0.995 times z4. Furthermore, u3 is preferably 0.986 to 0.995 times u1. Furthermore, v3 is preferably 1.194 to 1.577 times v1. Furthermore, w3 is preferably 0.986 to 0.995 times w1. Furthermore, x3 is preferably 0.986 to 0.995 times x1. Furthermore, y3 is preferably 0.986 to 0.995 times y1. Furthermore, z3 is preferably 0.986 to 0.995 times z1. Furthermore, u4 is preferably 1.000 to 1.015 times u1. Furthermore, v4 is preferably 0.406 to 1.000 times v1. Furthermore, w4 is preferably 1.000 to 1.015 times w1. Furthermore, x4 is preferably 1.000 to 1.015 times x1. Furthermore, y4 is preferably 1.000 to 1.015 times y1. Furthermore, z4 is preferably 1.000 to 1.015 times z1.

[0035] In the first region R1 where the ratio of the element represented by M0 is high, the compound containing Zn, O, and the element represented by M0 is Zn ｕ５ M0 ｖ５ C ｗ５N ｘ５ H ｙ５ O ｗ５ The compound has a relationship of Zn:M0:O:N:H:C=u5:v5:w5:x5:y5:z5, and satisfies u5+v5+w5+x5+y5+z5=2. In a second region P1 where the ratio of the element represented by M0 is low, the compound containing Zn, O, and the element represented by M0 is Zn. ｕ６ M0 ｖ６ C ｗ６ N ｘ６ H ｙ６ O ｗ６A compound represented by the formula (I) has a relationship of Zn:M0:O:N:H:C=u6:v6:w6:x6:y6:z6, where u6 + v6 + w6 + x6 + y6 + z6 = 2 is satisfied, and u5 is preferably 0.971 to 0.995 times u6, more preferably 0.981 to 0.995 times u6, and even more preferably 0.985 to 0.990 times u6. Furthermore, v5 is preferably 1.194 to 3.885 times v6, more preferably 1.244 to 2.942 times v6, and even more preferably 1.485 to 1.971 times v6. Furthermore, w5 is preferably 0.971 to 0.995 times w6. Furthermore, x5 is preferably 0.971 to 0.995 times x6. Furthermore, y5 is preferably 0.971 to 0.995 times y6. Furthermore, z5 is preferably 0.971 to 0.995 times z6. Furthermore, u5 is preferably 0.986 to 0.995 times u2. Furthermore, v5 is preferably 1.194 to 1.577 times v2. Furthermore, w5 is preferably 0.986 to 0.995 times w2. Furthermore, x5 is preferably 0.986 to 0.995 times x2. Furthermore, y5 is preferably 0.986 to 0.995 times y2. Furthermore, z5 is preferably 0.986 to 0.995 times z2. Furthermore, u6 is preferably 1 to 1.015 times u2. Furthermore, v6 is preferably 0.406 to 1 times v2. Furthermore, w6 is preferably 1 to 1.015 times w2. Furthermore, x6 is preferably 1 to 1.015 times x2. Furthermore, y6 is preferably 1 to 1.015 times y2. Furthermore, z6 is preferably 1 to 1.015 times z2.

[0036] From the viewpoint of reducing the resistance of the transparent electrode 10, the thickness of the first region R1 is preferably 0.4 nm to 1 nm, and the thickness of the second region P1 is preferably 0.4 nm to 1 nm. From the same viewpoint, the thickness of the first region R1 is more preferably 0.5 nm to 0.9 nm, and the thickness of the second region P1 is more preferably 0.5 nm to 0.9 nm. From the same viewpoint, the thickness of the first region R1 is even more preferably 0.5 nm to 0.8 nm, and the thickness of the second region P1 is even more preferably 0.5 nm to 0.8 nm.

[0037] The relationship between the first region R1 and the second region P1 can be confirmed, for example, by analyzing analysis spots A1 to A9 shown in FIG. 2 . D1 is the widthwise (X-direction) length of the transparent electrode 10. D2 is the depthwise (Y-direction) length of the transparent electrode 10. Note that both a configuration in which A1 to A9 are all the first region R1 or the second region P1 at a specific depth from the surface of the transparent electrode 10 and a configuration in which A1 to A9 are independently the first region R1 or the second region P1 are included. For example, if the position at a specific depth from the center A5 of the transparent electrode 10 is the first region R1, the first region R1 at the specific depth from the center A5 of the transparent electrode 10 is sandwiched between the second regions P1 in the thickness direction of the transparent electrode 10. In other words, when analyzing the transparent electrode 10 in the depth direction from any point on the surface of the transparent electrode 10, it is preferable that the first region R1 and the second region P1 are repeated in a range where the first region R1 and the second region P1 alternately exist twice or more times in the thickness direction of the transparent electrode 10. When analyzing the transparent electrode 10 in the depth direction from any point on the surface of the transparent electrode 10, analyzing a cross section of the transparent electrode 10 using a high-angle annular dark field scanning TEM (HAADF-STEM) can confirm from the pattern of brightness and darkness in the image that the first region R1 and the second region P1 alternately exist twice or more times in the thickness direction of the transparent electrode 10. Furthermore, analyzing a cross section of the transparent electrode 10 using SEM-EDX or TEM-EDX can confirm that the first region R1 and the second region P1 alternately exist twice or more times in the thickness direction of the transparent electrode 10. When analyzing using EDX, the beam diameter is preferably 0.1 nm or more and 5 nm or less, and the analysis depth is preferably approximately the thickness of the sample slice.

[0038] 3 is a graph showing the concentration of an element represented by M0 in the thickness direction of the transparent electrode 10 at analysis spots A1 to A3 among analysis spots A1 to A9. The vertical axis represents the depth direction. The horizontal axis represents the concentration of the element represented by M0 (higher concentration at the tip of the arrow). The concentration of the element represented by M0 at the intersection of the vertical and horizontal axes represents v1.

[0039] The concentration of the element represented by M0 preferably varies periodically in the thickness direction. The phase of the periodic variation of the concentration of the element represented by M0 may be shifted depending on the position in the transparent electrode 10. One period of the variation of the concentration of the element represented by M0 in the thickness direction of the transparent electrode 10 (the sum of the average thickness of the first region R1 and the average thickness of the second region P1) is preferably 0.8 nm or more and 2 nm or less. Having one period of 0.8 nm or more and 2 nm or less contributes to reducing the resistance of the transparent electrode 10. From the same viewpoint, one period of the variation of the concentration of the element represented by M0 in the thickness direction of the transparent electrode 10 is more preferably 1 nm or more and 1.8 nm or less, and even more preferably 1 nm or more and 1.6 nm or less.

[0040] The boundary between the first region R1 and the second region P1 is the position where the concentration of the element represented by M0 satisfies v1.

[0041] It is preferable that the transparent electrode 10 has a third region R2 in which the ratio of the element represented by M0 is high and a fourth region P2 in which the ratio of the element represented by M0 is low in the plane direction. It is preferable that a plurality of third regions R2 and a plurality of fourth regions P4 exist in the plane direction of the transparent electrode 10. It is preferable that the third region R2 in which the ratio of the element represented by M0 is high and the fourth region P2 in which the ratio of the element represented by M0 is low in the plane direction within a range in which the first region R1 and the second region P1 alternately exist two or more times in the thickness direction of the transparent electrode 10.

[0042] The range in which the third region R2 and the fourth region P2 alternate in the plane direction of the transparent electrode 10 (the area in the plane direction of the transparent electrode 10) is preferably 5% to 30% of the area of ​​the transparent electrode 10 (the cross-sectional area in the plane direction of the transparent electrode 10) within the range in which the first region R1 and the second region P1 alternately exist twice or more in the thickness direction of the transparent electrode 10 (within the area in the plane direction of the transparent electrode 10).

[0043] It is preferable that 3 atom % or more and 10 atom % or less in the third region R2 are elements represented by M0, it is more preferable that 4 atom % or more and 8 atom % or less are elements represented by M0, and it is even more preferable that 5 atom % or more and 7 atom % or less are elements represented by M0.

[0044] It is preferable that 1 atom % or more and 8 atom % or less in the fourth region P2 are elements represented by M0, it is more preferable that 2 atom % or more and 6 atom % or less are elements represented by M0, and it is even more preferable that 3 atom % or more and 5 atom % or less are elements represented by M0.

[0045] In the third region R2 where the ratio of the element represented by M0 is high, the relationship is Zn:M0:O:N:H:C = u7:v7:w7:x7:y7:z7, and in the fourth region P2 where the ratio of the element represented by M0 is low, the relationship is Zn:M0:O:N:H:C = u8:v8:w8:x8:y8:z8.

[0046] In the third region R2 where the ratio of the element represented by M0 is high, there is a relationship of Zn:M0:O:N:H:C = u7:v7:w7:x7:y7:z7, and u7 + v7 + w7 + x7 + y7 + z7 = 2 is satisfied. In the fourth region P2 where the ratio of the element represented by M0 is low, there is a relationship of Zn:M0:O:N:H:C = u8:v8:w8:x8:y8:z8, and u8 + v8 + w8 + x8 + y8 + z8 = 2 is satisfied. u7 is preferably 0.971 to 0.995 times u8, more preferably 0.981 to 0.995 times u8, and even more preferably 0.985 to 0.990 times u8. Furthermore, v7 is preferably 1.194 to 3.885 times v8, more preferably 1.244 to 2.942 times v8, and even more preferably 1.485 to 1.971 times v8. Furthermore, w7 is preferably 0.971 to 0.995 times w8. Furthermore, x7 is preferably 0.971 to 0.995 times x8. Furthermore, y7 is preferably 0.971 to 0.995 times y8. Furthermore, z7 is preferably 0.971 to 0.995 times z8. Furthermore, u7 is preferably 0.986 to 0.995 times u1. Furthermore, v7 is preferably 1.194 to 1.577 times v1. Furthermore, w7 is preferably 0.986 to 0.995 times w1. Furthermore, x7 is preferably 0.986 to 0.995 times x1. Furthermore, y7 is preferably 0.986 to 0.995 times y1. Furthermore, z7 is preferably 0.986 to 0.995 times z1. Furthermore, u8 is preferably 1 to 1.015 times u1. Furthermore, v8 is preferably 0.406 to 1 times v1. Furthermore, w8 is preferably 1 to 1.015 times w1. Furthermore, x8 is preferably 1 to 1.015 times x1. Furthermore, y8 is preferably 1 to 1.015 times y1. Furthermore, z8 is preferably 1 to 1.015 times z1.

[0047] In the third region R2 where the ratio of the element represented by M0 is high, the compound containing Zn, O, and the element represented by M0 is Zn ｕ９ M0 ｖ９ O ｗ９ N ｘ９ Hｙ９ C ｚ９ In a fourth region P2 where the ratio of the element represented by M0 is low, the compound containing Zn, O, and the element represented by M0 has a relationship of Zn:M0:O:N:H:C=u9:v9:w9:x9:y9:z9, and satisfies u9+v9+w9+x9+y9+z9=2. ｕ１０ M0 ｖ１０ O ｗ１０ N ｘ１０ H ｙ１０ C ｚ１０The compound is represented by the formula: Zn:M0:O:N:H:C = u10:v10:w10:x10:y10:z10, and satisfies u10 + v10 + w10 + x10 + y10 + z10 = 2. u9 is preferably 0.971 to 0.995 times u10, more preferably 0.981 to 0.995 times u10, and even more preferably 0.985 to 0.990 times u10. Furthermore, v9 is preferably 1.194 to 3.885 times v10, more preferably 1.244 to 2.942 times v10, and even more preferably 1.485 to 1.971 times v10. Furthermore, w9 is preferably 0.971 to 0.995 times w10. Furthermore, x9 is preferably 0.971 to 0.995 times x10. Furthermore, y9 is preferably 0.971 to 0.995 times y10. Furthermore, z9 is preferably 0.971 to 0.995 times z10. Furthermore, u9 is preferably 0.986 to 0.995 times u2. Furthermore, v9 is preferably 1.194 to 1.577 times v2. Furthermore, w9 is preferably 0.986 to 0.995 times w2. Furthermore, x9 is preferably 0.986 to 0.995 times x2. Furthermore, y9 is preferably 0.986 to 0.995 times y2. Furthermore, z9 is preferably 0.986 to 0.995 times z2. Furthermore, u10 is preferably 1 to 1.015 times u2. Furthermore, v10 is preferably 0.406 to 1 times v2. Furthermore, w10 is preferably 1 to 1.015 times w2. Furthermore, x10 is preferably 1 to 1.015 times x2. Furthermore, y10 is preferably 1 to 1.015 times y2. Furthermore, z10 is preferably 1 to 1.015 times z2.

[0048] From the viewpoint of reducing the resistance of the transparent electrode 10, the length of the third region R2 (the width of the third region R2 in the in-plane direction) is preferably 0.4 nm or more and 1 nm or less, and the length of the fourth region P2 (the width of the fourth region P2 in the in-plane direction) is preferably 0.4 nm or more and 1 nm or less. From the same viewpoint, the length of the third region R2 is more preferably 0.5 nm or more and 0.9 nm or less, and the length of the fourth region P2 is more preferably 0.5 nm or more and 0.9 nm or less. From the same viewpoint, the length of the third region R2 is even more preferably 0.5 nm or more and 0.8 nm or less, and the length of the fourth region P2 is even more preferably 0.5 nm or more and 0.8 nm or less.

[0049] The relationship between the third region R2 and the fourth region P2 can be confirmed by analyzing a cross section of the transparent electrode 10 in the plane direction using SEM-EDX or TEM-EDX. By analyzing the analysis spots A1 to A9 shown in Figure 2, the third region R2 and the fourth region P2 can be confirmed from the difference in concentration of the element represented by M0 in each spot. The analysis method for the third region R2 and the fourth region P2 is performed, for example, by evaluating the variation in concentration of the element represented by M0 in the analysis spots A1 to A9 at the same depth in the analysis of the first region R1 and the second region P1.

[0050] Next, a method for manufacturing the transparent electrode 10 will be described. The transparent electrode 10 is formed on a substrate. The substrate is, for example, a solar cell that does not have one electrode. More specifically, the transparent electrode is formed on the n-type layer of the solar cell. In addition to solar cells, the transparent electrode 10 can also be used as an electrode for display panels and the like.

[0051] The transparent electrode 10 is preferably manufactured by ALD. An organic compound containing an organozinc compound and an element represented by M0 is supplied as a precursor to a chamber to form the transparent electrode 10 on a substrate. The transparent electrode 10 of the embodiment can be obtained by reducing the deposition amount of the element represented by M0 per pulse without repeatedly increasing or decreasing the deposition amount of the element represented by M0 per pulse. By reducing the deposition amount of the element represented by M0 per pulse, it is possible to obtain a transparent electrode 10 in which the element represented by M0 is distributed at a suitable distance without increasing the concentration of the element represented by M0 in the transparent electrode 10. This transparent electrode 10 can achieve both low resistance and high transparency. The transparent electrode 10 of the embodiment can be obtained by reducing the deposition amount of the element represented by M0 per pulse.

[0052] The organic zinc compound is preferably at least one selected from the group consisting of dimethyl zinc, diethyl zinc, and the like.

[0053] The organic compound containing an element represented by M0 is preferably at least one selected from the group consisting of trimethylaluminum, triethylaluminum, trisdimethylamidoaluminum, trimethylgallium, trisdimethylamidogallium, trimethylborane, triethylborane, trisdimethylamidoborane, etc. From the viewpoint of obtaining the transparent electrode 10 of the embodiment, the organic compound containing an element represented by M0 is preferably a compound containing nitrogen.

[0054] From the viewpoint of producing a transparent electrode 10 in which the first regions R1 and the second regions P1 are alternately repeated, the ratio of the element represented by M0 to the nitrogen atoms in the organic compound containing the element represented by M0 ([number of moles of the element represented by M0 in the organic compound containing the element represented by M0] / [number of moles of nitrogen atoms in the organic compound containing the element represented by M0]) is preferably 0.3 or more and 1 or less, and more preferably 0.5 or more and 1 or less.

[0055] From the viewpoint of producing a transparent electrode 10 in which the first region R1 and the second region P1 are alternately repeated, it is preferable to produce the transparent electrode 10 by ALD. If the transparent electrode 10 is produced by sputtering, a highly uniform transparent electrode in which the first region R1 and the second region P1 are not alternately repeated will be obtained.

[0056] The transparent electrode 10 in which the first region R1 and the second region P1 are alternately repeated two or more times has high light transmittance, with a transmittance of 80% or more for light having a wavelength of 400 nm or more and 1300 nm or less. The transparent electrode 10 in which the first region R1 and the second region P1 are alternately repeated two or more times has improved transmittance for light having a wavelength of approximately 300 nm or more and approximately 1100 nm or less. The transparent electrode 10 of the embodiment is a conductive film that achieves both low resistance and light transmittance. Therefore, the transparent electrode 10 of the embodiment is suitable for use as a transparent electrode for devices such as solar cells and displays that require high transmittance for visible light.

[0057] Second Embodiment The second embodiment relates to a solar cell. FIG. 4 shows a schematic cross-sectional view of a solar cell 100 according to the second embodiment. As shown in FIG. 4, the solar cell 100 according to this embodiment includes a substrate 1, a p-electrode 2 (first electrode), a p-type light absorbing layer 3, an n-type layer 4, and an n-electrode 5 (second electrode). An intermediate layer (not shown) may be included between the n-type layer 4 and the n-electrode 5. Sunlight may be incident on either the n-electrode 5 side or the p-electrode 2 side, but it is more preferable for it to be incident on the n-electrode 5 side. Because the solar cell 100 according to this embodiment is a transparent solar cell, it is preferably used on the top cell side (light incident side) of a multi-junction solar cell. In FIG. 4, the substrate 1 is provided on the side opposite the p-electrode 2 from the p-type light absorbing layer 3. However, the substrate 1 may also be provided on the side opposite the n-electrode 5 from the n-type layer 4. The following describes the embodiment shown in FIG. 6. However, a similar embodiment is possible in which the substrate 1 is provided on the n-electrode 5 side, except for the position of the substrate 1. In the solar cell 100 of the embodiment, light is incident from the n-electrode 5 side toward the p-electrode 2 side.

[0058] In the solar cell 100 of the embodiment, when transparent electrodes are used for the p-electrode 2 and the n-electrode 5, the solar cell has high transmittance for light in the wavelength range of 700 nm or more and 1200 nm or less, and is a transparent solar cell with a reddish (reddish-brown), yellowish, or orange color.

[0059] The substrate 1 is a transparent substrate. The substrate 1 may be made of an organic substrate such as a light-transmitting acrylic, polyimide, polycarbonate, polyethylene terephthalate (PET), polypropylene (PP), fluorine-based resin (polytetrafluoroethylene (PTFE), perfluoroethylene propene copolymer (FEP), ethylene tetrafluoroethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), perfluoroalkoxyalkane (PFA)), polyarylate, polysulfone, polyethersulfone, or polyetherimide, or an inorganic substrate such as soda-lime glass, white plate glass, chemically strengthened glass, or quartz. The substrate 1 may be a laminate of the above-listed substrates.

[0060] The p-electrode 2 is provided on the substrate 1 and is disposed between the substrate 1 and the p-type light absorbing layer 3. The p-electrode 2 preferably forms an ohmic junction with the p-type light absorbing layer 3. The p-electrode 2 is a light-transmitting conductive layer provided on the p-type light absorbing layer 3 side. The thickness of the p-electrode 2 is typically 100 nm or more and 2000 nm or less. In FIG. 4 , the p-electrode 2 is in direct contact with the p-type light absorbing layer 3. The p-electrode 2 preferably includes one or more transparent conductive oxide films. Examples of the oxide transparent conductive film include semiconductor conductive films such as indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), boron-doped zinc oxide (BZO), gallium-doped zinc oxide (GZO), doped tin oxide, titanium-doped indium oxide (ITiO), indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), and hydrogen-doped indium oxide (IOH), and are not particularly limited. The oxide transparent conductive film may be a laminated film having a plurality of films. The dopant for the tin oxide film or the like is not particularly limited as long as it is one or more elements selected from the group consisting of In, Si, Ge, Ti, Cu, Sb, Nb, Ta, W, Mo, F, Cl, etc. The p-electrode 2 preferably includes a tin oxide film doped with one or more elements selected from the group consisting of In, Si, Ge, Ti, Cu, Sb, Nb, Ta, W, Mo, F, Cl, etc. In the doped tin oxide film, the one or more elements selected from the group consisting of In, Si, Ge, Ti, Cu, Sb, Nb, Ta, W, Mo, F, Cl, etc. are preferably contained in an amount of 10 atomic % or less relative to the tin contained in the tin oxide film. The p-electrode 2 can be a laminated film formed by stacking a transparent conductive oxide film and a metal film.The metal film preferably has a thickness of 1 nm or more and 2 μm or less, and the metal (including alloy) contained in the metal film is not particularly limited, and may be Mo, Au, Cu, Ag, Al, Ta, or W. The p-electrode 2 preferably includes a dot-shaped, line-shaped, or mesh-shaped electrode (one or more selected from the group consisting of metals, alloys, graphene, conductive nitrides, and conductive oxides) between the oxide transparent conductive film and the substrate 1, or between the oxide transparent conductive film and the p-type light absorbing layer 3. The dot-shaped, line-shaped, or mesh-shaped metal preferably has an aperture ratio of 50% or more relative to the oxide transparent conductive film. The dot-shaped, line-shaped, or mesh-shaped metal is not particularly limited, and may be Mo, Au, Cu, Ag, Al, Ta, or W. When a metal film is used for the p-electrode 2, the thickness is preferably about 5 nm or less from the viewpoint of transparency. When a line-shaped or mesh-shaped metal film is used, transparency is ensured by the apertures, so the thickness of the metal film is not limited thereto.

[0061] It is preferable that a doped tin oxide film be provided on the outermost surface of the oxide transparent conductive film on the side of the p-type light absorbing layer 3, forming an ohmic junction with the p-type light absorbing layer 3. It is preferable that at least a part of the doped tin oxide film provided on the outermost surface of the oxide transparent conductive film on the side of the p-type light absorbing layer 3 be in direct contact with the p-type light absorbing layer 3.

[0062] The p-type light absorbing layer 3 is a p-type semiconductor layer. The p-type light absorbing layer 3 is provided on the p-electrode 2. The p-type light absorbing layer 3 may be in direct contact with the p-electrode 2, or other layers may be present as long as electrical contact with the p-electrode 2 is ensured. The p-type light absorbing layer 3 is disposed between the p-electrode 2 and the n-type layer 4. Not the entire surface of the p-type light absorbing layer 3 facing the n-type layer 4, but a portion of the surface is in direct contact with the n-type layer 4. The p-type light absorbing layer 3 is mainly composed of a cuprous oxide compound. The cuprous oxide compound preferably has a cuprite structure.

[0063] The p-type light absorbing layer 3 is preferably a semiconductor layer containing a cuprous oxide compound. The p-type light absorbing layer 3 is preferably a polycrystalline cuprous oxide compound. The p-type light absorbing layer 3 contains copper (Cu), copper oxide (CuO), and copper hydroxide (Cu(OH)) as impurities. ２) may contain a trace amount of one or more cuprous oxide impurities selected from the group consisting of:

[0064] When all elements except oxygen contained in the p-type light absorbing layer 3 are taken as 100%, the copper element contained in the p-type light absorbing layer 3 is preferably 90% or more and 100% or less, more preferably 95% or more and 100% or less, more preferably 98% or more and 100% or less, and even more preferably 99% or more and 100% or less.

[0065] When the cuprous oxide compound contains elements other than copper and oxygen, when all elements excluding oxygen contained in the p-type light absorbing layer 3 are taken as 100%, the copper element contained in the p-type light absorbing layer 3 is preferably 90.0% or more and 99.9% or less, preferably 95.0% or more and 99.9% or less, more preferably 98% or less and 99.9% or less, and even more preferably 99.0% or more and 99.9% or less.

[0066] The cuprous oxide compound preferably contains copper and oxygen, and further contains an element represented by M1, which is preferably one or more elements selected from the group consisting of Cl, F, Br, I, Sn, Sb, Ag, Li, Na, K, Cs, Rb, Al, In, Zn, Mg, Ga, Si, Ge, N, P, B, Ti, Hf, Zr, and Ca.

[0067] When all elements except oxygen contained in the p-type light absorbing layer 3 are taken as 100%, the total of the copper element and the element represented by M1 contained in the p-type light absorbing layer 3 is preferably 95% or more and 100% or less, more preferably 98% or less and 100% or less, and even more preferably 99% or more and 100% or less.

[0068] The number of oxygen atoms contained in the cuprous oxide compound is preferably 0.48 or more and 0.56 or less, assuming that the number of copper atoms is 1. If the oxygen content is high relative to the copper content, the ratio of copper oxide contained in the cuprous oxide compound increases, narrowing the band gap and reducing the light transmittance of the p-type light absorbing layer 3, which is not preferred. If the oxygen content is low relative to the copper content, the copper content in the cuprous oxide compound increases, which is not preferred, as it reduces the light transmittance. Furthermore, if the ratio of oxygen to copper does not satisfy the above range, it becomes difficult for the cuprous oxide compound to have a cuprite structure.

[0069] Preferably, 95 wt % to 100 wt % of the p-type light absorbing layer 3 is a cuprous oxide compound, more preferably 98 wt % to 100 wt % of the p-type light absorbing layer 3 is a cuprous oxide compound, and even more preferably 99 wt % to 100 wt % of the p-type light absorbing layer 3 is a cuprous oxide compound. 100 wt % of the p-type light absorbing layer 3 can be composed of a cuprous oxide compound.

[0070] A p-type light absorbing layer 3 containing few heterophases and with good crystallinity is preferred because it has high light transmittance. The band gap of the p-type light absorbing layer 3 can be adjusted by, for example, including elements other than Cu and O in the p-type light absorbing layer 3. The band gap of the p-type light absorbing layer 3 is preferably 2.0 eV or more and 2.2 eV or less. With a band gap in this range, in a multi-junction solar cell using a solar cell with Si as the light absorbing layer as the bottom cell and the solar cell of the embodiment as the top cell, sunlight can be efficiently utilized in both the top cell and the bottom cell. The p-type light absorbing layer 3 preferably contains Sn and / or Sb. The Sn and Sb in the p-type light absorbing layer 3 may be added to the p-type light absorbing layer 3 or may be derived from the p-electrode 2. The Ga contained in the p-type light absorbing layer 3 is not contained in the raw materials used to form the p-type light absorbing layer 3, but is Ga contained in the n-type layer 4 diffused into the p-type light absorbing layer 3. If other elements are used when forming the n-type layer 4 , these elements may also diffuse into the p-type light absorbing layer 3 .

[0071] The composition ratio of the p-type light absorbing layer 3 is the composition ratio of the entire p-type light absorbing layer 3. The compound composition ratio of the p-type light absorbing layer 3 is preferably satisfied throughout the entire p-type light absorbing layer 3.

[0072] The p-type light absorbing layer 3 preferably has ap + -type (p plus type) region on the p-electrode 2 side.

[0073] The p-type light absorbing layer 3 preferably has a p-type (p minus type) region on the n-type layer side, and a p-type (p minus type) region on the p-electrode 2 side.

[0074] When elements of the n-type layer 4 diffuse into the p-type light absorbing layer 3 and / or elements of the p-type light absorbing layer 3 diffuse into the n-type layer 4, a mixed region having a thickness of 20 nm or less, where the elements have diffused, may exist between the p-type light absorbing layer 3 and the n-type layer 4. 90 atom % or less of the metal elements in the mixed region are the metal contained in the p-type light absorbing layer 3, and further 10 atom % or more of the metal elements in the mixed region are the metal elements contained in the n-type layer 4.

[0075] The thickness of the p-type light absorbing layer 3 is determined by cross-sectional observation using an electron microscope or a step gauge, and is preferably 2000 nm to 15000 nm (2 μm to 15 μm), more preferably 2500 nm to 10000 nm, even more preferably 4000 nm to 10000 nm, and preferably 4000 nm to 8000 nm. The p-type light absorbing layer 3 has a small uneven surface, and the difference between the minimum and maximum thicknesses of the p-type light absorbing layer 3 is preferably 0 nm to 100 nm, more preferably 0 nm to 50 nm. The p-type light absorbing layer 3 has a rectangular parallelepiped shape.

[0076] The p-type light absorbing layer 3 is preferably formed by, for example, a sputtering method. Specifically, the substrate 1 having the p-electrode 2 formed thereon is heated to 300°C to 600°C, and the oxygen partial pressure is preferably 0.01 Pa to 4.8 Pa and 0.02 μm / min to 20 μm / min. From the viewpoint of forming a polycrystalline film with high transparency and large grain size, the oxygen partial pressure is more preferably 0.55×d (0.55 multiplied by d) [Pa] to 1.00×d (1.00 multiplied by d) [Pa], where d is the deposition rate. Furthermore, the heating temperature is more preferably 350°C to 500°C. An element M1 can be added during film formation. After the p-type light absorbing layer 3 is formed, the surface on which the n-type layer 4 is to be formed may be oxidized before the n-type layer 4 is formed.

[0077] The n-type layer 4 is an n-type semiconductor layer. The n-type layer 4 is disposed between the p-type light absorbing layer 3 and the n-electrode 5. The n-type layer 4 is preferably provided on the p-type light absorbing layer 3. The n-type layer 4 is formed by, for example, an ALD method.

[0078] The n-type layer 4 located on the p-type light absorbing layer 3 side preferably contains a compound (oxide) mainly composed of Ga. The n-type layer 4 may be a mixture of an oxide mainly composed of Ga with other oxides, an oxide mainly composed of Ga doped with other elements, or a mixture of an oxide mainly composed of Ga doped with other elements and other oxides. The n-type layer 4 may be a single layer or a multilayer. Of the metal elements contained in the n-type layer 4 located on the p-type light absorbing layer 3 side, Ga is preferably 40 atomic % or more, more preferably 50 atomic % or more. The metal elements including Ga contained in the n-type layer 4 may be inclined from the p-type light absorbing layer 3 side toward the n-electrode 5 side. When the n-type layer 4 is a multilayer semiconductor layer (e.g., two layers), the layers are designated, from the p-type light absorbing layer 3 side, as a first n-type layer and a second n-type layer. The element represented by M2 contained in the first n-type layer is preferably less than the element represented by M2 contained in the second n-type layer. When the first n-type layer is a compound (oxide) containing Ga as the main component, the second n-type layer is preferably a compound (oxide) containing Sn or the like as the main component Zn.

[0079] The n-type layer 4 located on the p-type light absorbing layer 3 side preferably contains an oxide containing an element represented by M2 and Ga. The oxide containing Ga as a main component is, for example, an oxide containing an element represented by M2 and Ga. The n-type layer 4 located on the p-type light absorbing layer 3 side preferably contains an oxide containing Ga and M2, which is one or more elements selected from the group consisting of H, Sn, Sb, Cu, Ag, Li, Na, K, Cs, Rb, Al, In, Zn, Mg, Si, Ge, N, B, Ti, Hf, Zr, Ca, Ce, La, Pr, and Nd. The n-type layer 4 located on the p-type light absorbing layer 3 side preferably contains 90 wt % to 100 wt % of an oxide containing Ga and M2, which is one or more elements selected from the group consisting of H, Sn, Sb, Cu, Ag, Li, Na, K, Cs, Rb, Al, In, Zn, Mg, Si, Ge, N, B, Ti, Hf, Zr, Ca, Ce, La, Pr, and Nd. The compound containing Ga as the main component in the n-type layer 4 located on the p-type light absorbing layer 3 side preferably has an average composition of Ga. ｈ１ M2 ｉ１ O ｊ１ It is preferable that h1, i1, and j2 satisfy 1.8≦h1≦2.1, 0.0≦i1≦0.2, and 2.9≦j1≦3.1.

[0080] Preferably, 90 wt % to 100 wt % of the n-type layer 4 located on the p-type light absorbing layer 3 side is an oxide containing M2 and Ga. More preferably, 95 wt % to 100 wt % of the n-type layer 4 located on the p-type light absorbing layer 3 side is an oxide containing M2 and Ga. Even more preferably, 98 wt % to 100 wt % of the n-type layer 4 located on the p-type light absorbing layer 3 side is a compound represented by an oxide containing M2 and Ga. The Cu contained in the n-type layer 4 located on the p-type light absorbing layer 3 side is not contained in the raw materials used to form the n-type layer 4, but is Cu contained in the p-type light absorbing layer 3 that has diffused into the n-type layer 4. If other elements are used when forming the p-type light absorbing layer 3, these elements may also diffuse into the n-type layer 4.

[0081] The thickness of the n-type layer 4 is typically 3 nm or more and 100 nm or less. If the thickness of the n-type layer 4 is less than 3 nm, poor coverage of the n-type layer 4 may cause leakage current, resulting in degradation of characteristics. If coverage is good, the above thickness is not required. If the thickness of the n-type layer 4 exceeds 50 nm, degradation of characteristics due to excessively high resistance of the n-type layer 4 or a decrease in short-circuit current due to a decrease in transmittance may occur. Therefore, the thickness of the n-type layer 4 is more preferably 3 nm or more and 20 nm or less, and even more preferably 5 nm or more and 20 nm or less.

[0082] The n-electrode 5 is an electrode on the n-type layer 4 side that is optically transparent to visible light. The n-electrode 5 is the transparent electrode 10 of the first embodiment. The n-electrode 5 is preferably in direct contact with the n-type layer 4. The first region R1 or the second region P1 of the n-electrode 5 is preferably in direct contact with the n-type layer 4. The first region R1 or the second region P1 that is in direct contact with the n-type layer 4 is preferably located closest to the n-type layer 4 among the first regions R1 and second regions P1 that are alternately repeated two or more times in the thickness direction of the n-electrode 5.

[0083] When the second region P1 is in direct contact with the n-type layer 4, it is preferable that the second region P1, which is in direct contact with the n-type layer 4, the first region R1, the second region P1, and the first region R1 are arranged in this order from the surface of the n-type layer 4 side of the n-electrode 5 on the n-type layer 4 side toward the opposite side of the n-electrode 5 from the n-type layer 4 side, and that each opposing surface is in direct contact.

[0084] (Third Embodiment) The third embodiment relates to a multi-junction solar cell. Fig. 5 shows a cross-sectional conceptual diagram of a multi-junction solar cell of the third embodiment. The multi-junction solar cell 200 of Fig. 5 has a solar cell (first solar cell) 100 of the second embodiment and a second solar cell 201 on the light incident side. The light absorption layer of the second solar cell 201 has a band gap smaller than that of the p-type light absorption layer 3 of the solar cell 100 of the second embodiment. Note that the multi-junction solar cell 200 of this embodiment also includes a solar cell in which three or more solar cells are joined together.

[0085] Since the band gap of the p-type light absorbing layer (cuprous oxide) 3 of the first solar cell 100 of the second embodiment is approximately 2.0 eV or more and 2.2 eV or less, the band gap of the light absorbing layer of the second solar cell 201 is preferably 1.0 eV or more and 1.6 eV or less. The light absorbing layer of the second solar cell 201 is preferably one or more compound semiconductor layers selected from the group consisting of CIGS and CdTe systems with a high In content, or one type selected from the group consisting of crystalline silicon and perovskite compounds.

[0086] (Fourth embodiment) The fourth embodiment relates to a solar cell module. Fig. 6 shows a perspective view of a solar cell module 300 of the fourth embodiment. The solar cell module 300 of Fig. 6 is a solar cell module in which a first solar cell module 301 and a second solar cell module 302 are stacked. The first solar cell module 301 is on the light incident side and uses the solar cell 100 of the second embodiment. It is preferable to use the second solar cell 201 for the second solar cell module 302.

[0087] FIG. 7 shows a cross-sectional view of a solar cell module 300. FIG. 7 shows the structure of the first solar cell module 301 in detail, but does not show the structure of the second solar cell module 302. For the second solar cell module 302, an appropriate solar cell module structure is selected depending on the light absorption layer of the solar cell used, etc. The solar cell module 300 in FIG. 7 includes multiple submodules 303 surrounded by dashed lines, in which multiple solar cells 100 (solar cells) are arranged horizontally and electrically connected in series by wiring 304, and the multiple submodules 303 are electrically connected in parallel or in series. Adjacent submodules 303 are electrically connected by bus bars 305.

[0088] Adjacent solar cells 100 have their upper n-electrodes 5 and lower p-electrodes 2 connected by wiring 304. Similar to the solar cell 100 of the second embodiment, the solar cell 100 of the fourth embodiment also has a substrate 1, a p-electrode 2, a p-type light absorbing layer 3, an n-type layer 4, and an n-electrode 5. Both ends of the solar cells 100 in a submodule 303 are connected to a bus bar 305, and the bus bar 305 preferably connects the multiple submodules 303 electrically in parallel or in series to adjust the output voltage with the second solar cell module 302. Note that the connection configuration of the solar cells 100 shown in the fourth embodiment is one example, and solar cell modules can be configured using other connection configurations.

[0089] Fifth Embodiment The fifth embodiment relates to a solar power generation system. The solar cell module of the fifth embodiment can be used as a generator that generates power in the solar power generation system of the fifth embodiment. The solar power generation system of the embodiment generates power using a solar cell module. Specifically, the solar cell module generates power, a means for converting the generated electricity, and a storage means for storing the generated electricity or a load for consuming the generated electricity. FIG. 8 shows a configuration diagram of a solar power generation system 400 of the embodiment. The solar power generation system of FIG. 8 includes a solar cell module 401 (300), a converter 402, a storage battery 403, and a load 404. Either the storage battery 403 or the load 404 may be omitted. The load 404 may be configured to utilize the electrical energy stored in the storage battery 403. The converter 402 is a device including a circuit or element that performs power conversion such as voltage transformation or DC-AC conversion, such as a DC-DC converter, a DC-AC converter, or an AC-AC converter. The converter 402 may have a suitable configuration depending on the power generation voltage and the configurations of the storage battery 403 and the load 404 .

[0090] The solar cell included in the submodule 303 included in the solar cell module 401 receives light and generates electricity, and the electrical energy is converted by the converter 402 and stored in the storage battery 403 or consumed by the load 404. The solar cell module 401 is preferably provided with a solar tracking drive device for always directing the solar cell module 401 toward the sun, a light collector for collecting sunlight, or other devices for improving power generation efficiency.

[0091] The solar power generation system 400 is preferably used in real estate such as residences, commercial facilities, factories, etc., or in movable property such as vehicles, aircraft, electronic devices, etc. By using the solar cell with excellent conversion efficiency of the embodiment in a solar cell module, an increase in the amount of power generation is expected.

[0092] A vehicle is shown as an example of a use of the solar power generation system 400. FIG. 9 shows a conceptual diagram of the vehicle 500. The vehicle 500 in FIG. 9 includes a vehicle body 501, a solar cell module 502, a power converter 503, a storage battery 504, a motor 505, and tires (wheels) 506. The power generated by the solar cell module 502 installed on the top of the vehicle body 501 is converted by the power converter 503 and charged in the storage battery 504, or consumed by loads such as the motor 505. The vehicle 500 can be driven by rotating the tires (wheels) 506 using power supplied from the solar cell module 502 or the storage battery 504 via the motor 505. The solar cell module 502 need not be a multi-junction type, but may be composed solely of a first solar cell module including the solar cell 100 of the first embodiment. When a transparent solar cell module 502 is used, it is also preferable to use the solar cell module 502 as a power generation window on the side of the vehicle body 501 in addition to the top of the vehicle body 501.

[0093] An air vehicle (drone) is shown as an example of use of the solar power generation system 400. The air vehicle uses a solar cell module 401. The configuration of the air vehicle according to this embodiment will be briefly described using the schematic diagram of an air vehicle 600 in FIG. 10. The air vehicle 600 has a solar cell module 401, a body frame 601, a motor 602, a rotor 603, and a control unit 604. The solar cell module 401, the motor 602, the rotor 603, and the control unit 604 are arranged on the body frame 601. The control unit 604 converts the power output from the solar cell module 401 and adjusts the output. The motor 602 uses the power output from the solar cell module 401 to rotate the rotor 603. By using the air vehicle 600 with this configuration and the solar cell module 401 according to the embodiment, an air vehicle that can fly using more power is provided.

[0094] Sixth Embodiment The sixth embodiment relates to a display device. The display device has transparent electrodes sandwiching a liquid crystal layer or a light-emitting layer. FIG. 11 is a schematic diagram of a display device 700 using a transparent electrode 10. The display device 700 has a first electrode 701, a second electrode 702, and an intermediate layer 703 including a liquid crystal layer or a light-emitting layer. The transparent electrode 10 of the embodiment is used for the first electrode 701 and / or the second electrode 702. It is preferable to use a transparent electrode 10 with low resistance and high light transmittance as the transparent electrode of the display device 700.

[0095] The present invention will be described in more detail below based on examples, but the present invention is not limited to the following examples.

[0096] (Example A) (Example A1) ITO (In:Sn=80:20, film thickness 150 nm) and ATO (Sn:Sb=98:2, film thickness 100 nm) are deposited on the upper surface of a glass substrate 1, on the side in contact with the glass, as a p-electrode 2 on the rear side. A 6 μm-thick Cu film is deposited on the ATO as a p-type light absorbing layer 3 by sputtering in an oxygen and argon gas atmosphere. ２ After the p-type light absorbing layer 3 is formed, a GaO layer having a thickness of 10 nm is formed as the n-type layer 4. ２ O ３A film is formed. Then, a transparent electrode is formed by ALD as the n-electrode 5 so that the thickness is 50 [nm] and the Al content is 5% relative to the Zn. The transparent electrode u1(Zn):v1(Al):w1(O):x1(N):y1(H):z1(C) = 0.97466:0.04873:0.97466:0.00016:0.00162:0.00016. When forming the transparent electrode, the deposition amount of Al per pulse is adjusted to be medium (example standard). The deposition conditions are adjusted so that the deposition amount of Al per pulse in Example A1 is generally the same.

[0097] A solar simulator simulating an AM1.5G light source is used, and the light intensity is adjusted to 1 sun using a reference Si cell under that light source. Measurements are performed under atmospheric pressure with the temperature in the measurement room at 25°C. The voltage is swept and the short-circuit current density (Jsc) (current divided by cell area) is measured. With the horizontal axis representing voltage and the vertical axis representing current density, the point where they intersect with the horizontal axis is the open-circuit voltage (Voc). On the measurement curve, multiply the voltage and short-circuit current density, and define the maximum points as Vmpp and Jmpp (maximum power point), respectively. The fill factor can be calculated as FF = (Vmpp * Jmpp) / (Voc * Jsc). The conversion efficiency can be calculated as Eff. = Voc * Jsc * FF.

[0098] The light transmittance is evaluated as A when the light transmittance in the wavelength band of 700 nm or more and 1000 nm or less is 75% or more, as B when the light transmittance in the wavelength band of 700 nm or more and 1000 nm or less is 70% or more and less than 75%, and as C when the light transmittance in the wavelength band of 700 nm or more and 1000 nm or less is less than 70%. The evaluation of light transmittance is common to Example A and Examples other than Example A.

[0099] Jsc is 11 [mA / cm ２ ] or more is evaluated as A, and 8 [mA / cm ２ ] or more 11 [mA / cm ２ ] is evaluated as B, and 8 [mA / cm ２ If the value is less than 1, it is evaluated as C. The evaluation of FF is common to Example A and Examples other than Example A.

[0100] When Voc is 1.2 V or more, it is evaluated as A, when it is 1.1 V or more and 1.2 V or less, it is evaluated as B, and when it is 1.1 V, it is evaluated as C. The evaluation of Voc is common to Example A and Examples other than Example A.

[0101] FF is evaluated as A when it is 0.65 [-] or more, as B when it is 0.6 [-] or more and less than 0.65 [-], and as C when it is 0.6 [-]. The FF evaluation is common to Example A and Examples other than Example A.

[0102] Conversion efficiency of 8.5% or more was evaluated as A, 6% or more and 8.5% or less was evaluated as B, and less than 6% was evaluated as C. The evaluation of conversion efficiency is common to Example A and examples other than Example A.

[0103] Regarding the dispersibility of the element represented by M0, a case in which the first region R1 and the second region P1 are repeated two or more times in the thickness direction of the n-electrode 5 in the n-electrode 5 is evaluated as A, and a case in which the first region R1 and the second region P1 are not repeated in the thickness direction of the n-electrode 5 is evaluated as B. In other words, when the dispersibility of the element represented by M0 is evaluated as A, the element represented by M0 is dispersed with a sparse / dense distribution in the thickness direction of the transparent electrode 10 in the compound containing Zn, O, and the element represented by M0. Furthermore, when the dispersibility of the element represented by M0 is evaluated as A, the element represented by M0 is dispersed with anisotropy in the thickness direction of the transparent electrode 10 in the compound containing Zn, O, and the element represented by M0.

[0104] (Comparative Example A1-1) ITO (In:Sn=80:20, film thickness 150 nm) and ATO (Sn:Sb=98:2, film thickness 100 nm) are deposited on the upper surface of a glass substrate 1, on the side in contact with the glass, as a p-electrode 2 on the rear surface side. A 6 μm-thick Cu film is deposited on the ATO as a p-type light absorbing layer 3 by sputtering in an oxygen and argon gas atmosphere. ２ After the p-type light absorbing layer 3 is formed, a GaO layer having a thickness of 10 nm is formed as the n-type layer 4. ２ O ３A film is formed. Then, a 50-nm-thick AZO (ZnO containing approximately 5% Al) transparent electrode is formed as the n-electrode 5 by ALD to obtain the solar cell 100. The ratios u1(Zn):v1(Al):w1(O):x1(N):y1(H):z1(C) were 0.97466:0.04873:0.97466:0.00016:0.00162:0.00016. When forming the transparent electrode, the Al deposition amount per pulse in Comparative Example A1 is approximately twice the deposition amount per pulse of the element represented by Al when forming the transparent electrode of the Example. The deposition conditions are adjusted so that the Al deposition amount per pulse in Comparative Example A1 is approximately the same overall. To adjust the composition, one period of concentration change of the element represented by M0 (the sum of the average thickness of the first region R1 and the average thickness of the second region P1) is approximately doubled. Then, the solar cell is evaluated in the same manner as in Example A1.

[0105] (Comparative Example A1-2) ITO (In:Sn=80:20, film thickness 150 nm) and ATO (Sn:Sb=98:2, film thickness 100 nm) are deposited on the upper surface of a glass substrate 1, on the side in contact with the glass, as a p-electrode 2 on the rear surface side. A Cu layer with a thickness of 6 μm is deposited on the ATO as a p-type light absorbing layer 3 by sputtering in an oxygen and argon gas atmosphere. ２ After the p-type light absorbing layer 3 is formed, a GaO layer having a thickness of 10 nm is formed as the n-type layer 4. ２ O ３A film is formed. Then, a 50 nm thick AZO (ZnO containing approximately 5% Al) transparent electrode is formed as the n-electrode 5 by ALD to obtain the solar cell 100. The ratios u1(Zn):v1(Al):w1(O):x1(N):y1(H):z1(C) were 0.97466:0.04873:0.97466:0.00016:0.00162:0.00016. When forming the transparent electrode, the film is formed so that the amount of Al deposited per pulse in Comparative Example A1 is approximately half the amount of Al deposited per pulse in the transparent electrode of the example. The film formation conditions are adjusted so that the amount of Al deposited per pulse in Comparative Example A1 is generally the same. To adjust the composition, one period of the concentration change of the element represented by M0 (the sum of the average thickness of the first region R1 and the average thickness of the second region P1) is set to about 1 / 2. Then, the solar cell is evaluated in the same manner as in Example A1.

[0106] (Examples A2 to A5, Comparative Examples A2-1 to A6-1, Comparative Examples A2-2 to A6-2) The solar cells 100 of Examples A2 to A6, Comparative Examples A2-1 to A6-1, and Comparative Examples A2-2 to A6-2 were fabricated by changing the conditions for forming the n-electrode 5, which is the transparent electrode 10. The film formation conditions for the n-electrode 5 of the solar cell of Example A are shown in the table of FIG. 12. The evaluation results of the solar cell of Example A are shown in the table of FIG. 13. The film formation conditions were adjusted so that the deposition amount per pulse of the element represented by M0 when forming the transparent electrode of the comparative example for comparison was approximately twice or approximately one-half the deposition amount per pulse of the element represented by M0 when forming the transparent electrode of the example. The film formation conditions were adjusted so that the deposition amount of Al per pulse of the examples and comparative examples was generally similar.

[0107] When forming the AZO transparent electrode of Example A, if the amount of M0 deposited per pulse is high relative to the medium level (based on the example), the R1 + P1 period must be lengthened to maintain the same concentration of M0. When the amount of M0 deposited per pulse increases, this layer becomes a resistive component, increasing its insulating properties and decreasing Jsc and conversion efficiency. Furthermore, as the R1 + P1 period increases, the ZnO layer containing less M0 becomes thicker, resulting in a decrease in transmittance. On the other hand, when the amount of M0 deposited per pulse is low relative to the medium level (based on the example), the R1 + P1 period must be shortened to maintain the same concentration of M0. As the R1 + P1 period shortens, the layers containing highly insulating M0 become closer, increasing the resistance of AZO and decreasing Jsc and conversion efficiency. Transmittance increases due to the increase in the number of oxide layers containing wide-gap M0.

[0108] (Example B) (Example B1) ITO (In:Sn=80:20, film thickness 150 nm) and ATO (Sn:Sb=98:2, film thickness 100 nm) are deposited on the upper surface of a glass substrate 1, on the side in contact with the glass, as a p-electrode 2 on the rear side. A Cu layer with a thickness of 6 μm is deposited on the ATO as a p-type light absorbing layer 3 by sputtering in an oxygen and argon gas atmosphere. ２ After the p-type light absorbing layer 3 is formed, a GaO layer is formed as an n-type layer 4 (first n-layer) having a thickness of 10 nm. ２ O ３ A film is formed. ２ O ３ A 14 nm thick ZnSnO (Zn:Sn = 80:20) film is formed on the n-layer as the second n-layer. Then, a 50 nm thick AZO (ZnO containing approximately 5% Al) transparent electrode is formed by ALD as the n-electrode 5 to obtain the solar cell 100. The ratios of u1(Zn):v1(Al):w1(O):x1(N):y1(H):z1(C) were 0.97466:0.04873:0.97466:0.00016:0.00162:0.00016. When forming the transparent electrode, the deposition amount of Al per pulse was adjusted to be medium overall. The deposition conditions for Example B1 were adjusted so that the deposition amount of Al per pulse was approximately the same overall. The solar cell was then evaluated in the same manner as in Example A1.

[0109] (Comparative Example B1-1) ITO (In:Sn=80:20, film thickness 150 nm) and ATO (Sn:Sb=98:2, film thickness 100 nm) are deposited on the upper surface of a glass substrate 1, on the side in contact with the glass, as a p-electrode 2 on the rear surface side. A 6 μm-thick Cu film is deposited on the ATO as a p-type light absorbing layer 3 by sputtering in an oxygen and argon gas atmosphere. ２ After the p-type light absorbing layer 3 is formed, a GaO layer having a thickness of 10 nm is formed as the n-type layer 4. ２ O ３ A film is formed. ２ O ３ A 14 nm thick ZnSnO (Zn:Sn = 80:20) film is formed on top as the second n-layer. Then, a 50 nm thick AZO (ZnO containing approximately 5% Al) transparent electrode is formed by ALD as the n-electrode 5 to obtain the solar cell 100. The ratios of u1(Zn):v1(Al):w1(O):x1(N):y1(H):z1(C) were 0.97466:0.04873:0.97466:0.00016:0.00162:0.00016. When forming the transparent electrode, the film is formed so that the overall deposition amount of Al per pulse is approximately twice the deposition amount of the element represented by Al per pulse when forming the transparent electrode of the example. The deposition conditions are adjusted so that the deposition amount of Al per pulse of Comparative Example B1 is generally the same. To adjust the composition, one period of the concentration change of the element represented by M0 (the sum of the average thickness of the first region R1 and the average thickness of the second region P1) is approximately doubled. Then, the solar cell is evaluated in the same manner as in Example A1.

[0110] (Comparative Example B1-2) ITO (In:Sn=80:20, film thickness 150 nm) and ATO (Sn:Sb=98:2, film thickness 100 nm) are deposited on the upper surface of a glass substrate 1, on the side in contact with the glass, as a p-electrode 2 on the rear surface side. A 6 μm-thick Cu film is deposited on the ATO as a p-type light absorbing layer 3 by sputtering in an oxygen and argon gas atmosphere. ２ After the p-type light absorbing layer 3 is formed, a GaO layer having a thickness of 10 nm is formed as the n-type layer 4. ２ O ３ A film is formed. ２ O ３A 14 nm thick ZnSnO (Zn:Sn = 80:20) film is formed on top as the second n-layer. Then, a 50 nm thick AZO (ZnO containing approximately 5% Al) transparent electrode is formed by ALD as the n-electrode 5 to obtain the solar cell 100. The ratios of u1(Zn):v1(Al):w1(O):x1(N):y1(H):z1(C) were 0.97466:0.04873:0.97466:0.00016:0.00162:0.00016. When forming the transparent electrode, the film is formed so that the overall deposition amount of Al per pulse is approximately half the deposition amount per pulse of the element represented by Al when forming the transparent electrode of the example. The deposition conditions are adjusted so that the deposition amount of Al per pulse of Comparative Example B1 is generally the same. To adjust the composition, one period of the concentration change of the element represented by M0 (the sum of the average thickness of the first region R1 and the average thickness of the second region P1) is set to about 1 / 2. Then, the solar cell is evaluated in the same manner as in Example A1.

[0111] (Examples B2 to B5, Comparative Examples B2-1 to B6-1, Comparative Examples B2-2 to B6-2) Solar cells of Examples B2 to B6, Comparative Examples B2-1 to B6-1, and Comparative Examples B2-2 to B6-2 were fabricated by changing the conditions for forming the n-electrode 5, which is the transparent electrode 10. The film formation conditions for the n-electrode 5 of the solar cell of Example B are shown in the table of FIG. 14. The evaluation results of the solar cell of Example B are shown in the table of FIG. 15. The film formation conditions were adjusted so that the deposition amount per pulse of the element represented by M0 when forming the transparent electrode of the comparative example for comparison was approximately twice or approximately one-half the deposition amount per pulse of the element represented by M0 when forming the transparent electrode of the example. The film formation conditions were adjusted so that the deposition amount of Al per pulse of the examples and comparative examples was generally similar.

[0112] In Example A, the AZO transparent electrode is GaO ３ In Example B, the AZO transparent electrode was deposited on a ZnSnO film, whereas in Example C, it was deposited on a ZnSnO film. Regardless of the underlayer, the solar cell performance and transmittance exhibit similar characteristics with the AZO transparent electrode.

[0113] Although the embodiments of the present invention have been described above, the present invention should not be construed as being limited to the above-described embodiments, and the components can be modified and embodied in practice without departing from the spirit of the invention. Furthermore, various inventions can be formed by appropriately combining multiple components disclosed in the above-described embodiments. For example, components from different embodiments may be appropriately combined, as in modified examples.

[0114] In the specification, some elements are shown only by their element symbols.

[0115] Technical proposals of the embodiments are listed below. Technical proposal 1: A transparent electrode mainly composed of a compound containing an element represented by Zn, O, and M0, wherein the element represented by M0 is dispersed in the compound containing the element represented by Zn, O, and M0 with a sparse / dense distribution in the thickness direction. Technical proposal 2: A transparent electrode according to Technical proposal 1, wherein first regions having a high ratio of the element represented by M0 and second regions having a low ratio of the element represented by M0 are alternately repeated at least twice in the thickness direction. Technical proposal 3: A transparent electrode according to any one of Technical proposals 1 or 2, wherein the compound further contains N. Technical proposal 4: A transparent electrode according to any one of Technical proposals 1 to 4, wherein the element represented by M0 accounts for 1 atom % to 10 atom % in the transparent electrode. Technical proposal 5: A transparent electrode according to Technical proposal 2, wherein the element represented by M0 accounts for 3 atom % to 10 atom % in the first region, and the element represented by M0 accounts for 1 atom % to 8 atom % in the second region. Technical Suggestion 6: A transparent electrode according to Technical Suggestion 2 or 5, wherein in the first region, a relationship of Zn:M0:O:N:H:C = u3:v3:w3:x3:y3:z3 exists, and u3 + v3 + w3 + x3 + y3 + z3 = 2 is satisfied; and in the second region, a relationship of Zn:M0:O:N:H:C = u4:v4:w4:x4:y4:z4 exists, and u4 + v4 + w4 + x4 + y4 + z4 = 2 is satisfied; and v3 is 1.194 times or more and 3.885 times or less than v4.Technical Proposal 7 In the compound containing elements represented by Zn, O, and M0, there is a relationship of Zn:M0:O:N:H:C = u1:v1:w1:x1:y1:z1, and u1 + v1 + w1 + x1 + y1 + z1 = 2, 0.95 ≤ (u1 + v1) ≤ 1.15, u1 > 0, and v1 > 0 are satisfied; in the first region, there is a relationship of Zn:M0:O:N:H:C = u3:v3:w3:x3:y3:z3, and u3 + v3 + w3 + x3 + y3 + z3 = 2 is satisfied; and in the second region, there is a relationship of Zn:M0:O:N:H:C = u4:v4:w4:x4:y4:z4, and u4 + v4 + w4 + x4 + y4 + z4 = 2 is satisfied, and v3 is 1.19 of v4. 4 times or more and 3.885 times or less, u3 is 0.971 times or more and 0.995 times or less of u4, w3 is 0.971 times or more and 0.995 times or less of w4, y3 is 0.971 times or more and 0.995 times or less of y4, z3 is 0.971 times or more and 0.995 times or less of z4, u3 is 0.986 times or more and 0.995 times or less of u1, and v3 is v1 x3 is 0.986 times or more and 0.995 times or less than x1; y3 is 0.986 times or more and 0.995 times or less than y1; z3 is 0.986 times or more and 0.995 times or less than z1; u4 is 1.000 times or more and 1.015 times or less than u1; Zn, O, and z4 are each independently selected from the group consisting of Zn, O, and M0. Technical Suggestion 8: The transparent electrode according to any one of Technical Suggestions 1 to 7, wherein Zn is 0.406 to 1.000 times v1, w4 is 1.000 to 1.015 times w1, x4 is 1.000 to 1.015 times x1, y4 is 1.000 to 1.015 times y1, and z4 is 1.000 to 1.015 times z1. Technical Suggestion 9: The transparent electrode according to any one of Technical Suggestions 1 to 8, wherein Zn, O, and z4 are each independently selected from the group consisting of Zn, O, and M0. Technical Suggestion 9: The transparent electrode according to any one of Technical Suggestions 1 to 8, wherein one period of change in concentration of the element represented by M0 in the thickness direction of the transparent electrode is 0.8 nm to 2 nm.Technical Suggestion 10: The transparent electrode according to any one of Technical Suggestions 2, 5 to 7, wherein the range in which the first high regions and the second high regions are alternately repeated two or more times in the thickness direction of the transparent electrode accounts for 80% to 100% of the thickness of the transparent electrode. Technical Suggestion 11: A solar cell comprising: a p-electrode; an n-electrode; a p-type light absorbing layer mainly made of a cuprous oxide compound provided on the p-electrode; an n-type layer provided between the p-type light absorbing layer and the n-electrode; and the transparent electrode according to any one of Technical Suggestions 1 to 10 provided on the n-type layer. Technical Suggestion 12: A multi-junction solar cell using the solar cell according to Technical Suggestion 11. Technical Suggestion 13: A solar cell module using the solar cell according to Technical Suggestion 11. Technical Suggestion 14: A solar power generation system that generates electricity using the solar cell module according to Technical Suggestion 13.

[0116] 10: Transparent electrode 1: Substrate 2: P-electrode 3: P-type light absorption layer 4: N-type layer 5: N-electrode 100: Solar cell 200: Multi-junction solar cell 201: Second solar cell 300: Solar cell module 301: First solar cell module 302: Second solar cell module 303: Sub-module 304: Wiring 305: Bus bar 400: Solar power generation system 401: Solar cell module 402: Converter 403: Storage battery 404: Load 500: Vehicle 501: Vehicle body 502: Solar cell module 503: Power conversion device 504: Storage battery 505: Motor 600: Flying object 601: Airframe frame 602: Motor 603: Rotor 604: Control unit

Claims

1. The compound mainly consists of elements represented by Zn, O, and M0. The element represented by M0 is dispersed in a compound containing Zn, O, and the element represented by M0, with a density distribution in the thickness direction, in a transparent electrode.

2. The transparent electrode according to claim 1, wherein a first region having a high proportion of the element represented by M0 and a second region having a low proportion of the element represented by M0 are alternately repeated two or more times in the thickness direction.

3. The transparent electrode according to claim 1, further comprising N as the compound.

4. The transparent electrode according to claim 1, wherein 1 atom% to 10 atom% of the transparent electrode is the element represented by M0.

5. The amount of 3 [atom%] to 10 [atom%] in the first region is the element represented by M0, The transparent electrode according to claim 2, wherein 1 atom% to 8 atom% of the second region is an element represented by M0.

6. The transparent electrode according to claim 2, wherein in the first region, the relationship Zn:M0:O:N:H:C = u3:v3:w3:x3:y3:z3 is met and u3+v3+w3+x3+y3+z3=2 is satisfied, and in the second region, the relationship Zn:M0:O:N:H:C = u4:v4:w4:x4:y4:z4 is met and u4+v4+w4+x4+y4+z4=2 is satisfied, and v3 is 1.194 times or more and 3.885 times or less of v4.

7. In the compound containing the elements represented by Zn, O, and M0, the relationship Zn:M0:O:N:H:C = u1:v1:w1:x1:y1:z1 is satisfied, and u1+v1+w1+x1+y1+z1=2, 0.95≦(u1+v1)≦1.15, u1>0, and v1>0. In the first region, the relationship Zn:M0:O:N:H:C = u3:v3:w3:x3:y3:z3 exists, satisfying u3 + v3 + w3 + x3 + y3 + z3 = 2. In the second region, the relationship Zn:M0:O:N:H:C = u4:v4:w4:x4:y4:z4 exists, satisfying u4 + v4 + w4 + x4 + y4 + z4 = 2, where v3 is 1 of v4. . The ratio is between 194 and 3.885, u3 is between 0.971 and 0.995 times u4, w3 is between 0.971 and 0.995 times w4, y3 is between 0.971 and 0.995 times y4, z3 is between 0.971 and 0.995 times z4, u3 is between 0.986 and 0.995 times u1, v3 is between 1.194 and 1.577 times v1, w3 is between 0.986 and 0.995 times w1, x3 is between 0.986 and 0.995 times x1, y3 is between 0.986 and 0.995 times y1, z3 is between 0.986 and 0.995 times z1, and u4 is between 1.000 and 1.01 times u1. The transparent electrode according to claim 2, wherein the ratio is 5 times or less, v4 is 1.000 times or more and 1.015 times or less of v1, w4 is 1.000 times or more and 1.015 times or less of w1, x4 is 1.000 times or more and 1.015 times or less of x1, y4 is 1.000 times or more and 1.015 times or less of y1, and z4 is 1.000 times or more and 1.015 times or less of z1.

8. The transparent electrode according to claim 1, wherein 95 [wt%] to 100 [wt%] of the transparent electrode is a compound containing the elements represented by Zn, O, and M0.

9. The transparent electrode according to claim 1, wherein one period of the change in the concentration of the element represented by M0 in the thickness direction of the transparent electrode is 0.8 [nm] or more and 2 [nm] or less.

10. The transparent electrode according to claim 2, wherein the range in which the high first region and the second region alternately exist two or more times in the thickness direction of the transparent electrode is 80% or more and 100% or less of the thickness of the transparent electrode.

11. p electrode and, n electrode and, A p-type light-absorbing layer mainly composed of a cuprous oxide compound is provided on the p-electrode, An n-type layer is provided between the p-type light absorbing layer and the n-electrode, A transparent electrode according to any one of claims 1 to 10 is provided on the n-type layer, A solar cell.

12. A multi-junction solar cell using the solar cell described in claim 11.

13. A solar cell module using the solar cell described in claim 11.

14. A solar power generation system that generates electricity using the solar cell module described in claim 13.