Ion irradiation method for element doping of flexible CIGS film

Abstract

The invention belongs to the technical field of alkali metal elements, and particularly relates to an ion irradiation method for element doping of a flexible CIGS film, which comprises the following specific steps: keeping a substrate at a set temperature, then turning on In, Ga and Se evaporation sources to deposit In, Ga and Se on the substrate, turning off the In and Ga evaporation sources after deposition, and turning off the In, Ga and Se evaporation sources after deposition. The temperature of the substrate is raised, when the temperature of the substrate is raised to the set temperature, the Cu evaporation source is turned on, and the required temperature of the substrate is kept. According to the method, the ion implantation amount and depth and the distribution of ions in the film can be accurately controlled, and various ions can be simultaneously implanted, so that the synergistic effect of alkali metal elements on the film quality and the improvement of the battery efficiency can be fully verified.

Description

Technical Field

[0001] The invention relates to the technical field of alkali metal elements, and in particular to an ion irradiation method for performing element doping on a flexible copper indium gallium selenide film. Background Art

[0002] Alkali metal elements play a very important role in improving the crystallization state of copper indium gallium selenide thin films, increasing carrier concentration, reducing carrier recombination, and passivating semiconductor defects. Therefore, alkali metal element doping is one of the indispensable means to improve the performance of copper indium gallium selenide devices. Traditional copper indium gallium selenide photovoltaic devices use soda-lime glass as a substrate. During the film deposition process, the alkali metal elements in the glass substrate can slowly diffuse into the copper indium gallium selenide film driven by the process temperature. When a flexible substrate (generally stainless steel or polyacetamide) is used, since the substrate does not contain alkali metal elements, alkali metal elements need to be doped during the deposition process. At present, the alkali metal element doping of flexible copper indium gallium selenide films mainly adopts the method of first depositing back electrode molybdenum on the substrate and then depositing a layer of alkali metal elements (sodium, potassium, cesium).

[0003] The disadvantage of the prior art is that the distribution of alkali metals depends entirely on the thermodynamic diffusion of alkali metal elements, which leads to uneven distribution of alkali metal elements in the film, thereby deteriorating the uniformity of film performance and being detrimental to improving battery efficiency. Therefore, an ion irradiation method for element doping of a flexible copper indium gallium selenide film is invented. Summary of the invention

[0004] In view of the above problems and / or the problems existing in the existing ion irradiation method for element doping of a flexible copper indium gallium selenide film, the present invention is proposed.

[0005] Therefore, the purpose of the present invention is to provide an ion irradiation method for element doping of a flexible copper indium gallium selenide film, which can solve the above-mentioned existing problems.

[0006] To solve the above technical problems, according to one aspect of the present invention, the present invention provides the following technical solutions:

[0007] An ion irradiation method for element doping of a flexible copper indium gallium selenide film comprises the following specific steps:

[0008] Step 1: Keep the substrate at a set temperature, then turn on the In, Ga, and Se evaporation sources to deposit In, Ga, and Se on the substrate;

[0009] Step 2: Turn off the In and Ga evaporation sources and increase the substrate temperature. When the substrate rises to the set temperature, turn on the Cu evaporation source and keep the substrate at the required temperature.

[0010] Step 3: When the substrate temperature drops, the Cu evaporation source is turned off, and the In and Ga evaporation sources are turned on. After 5 minutes of deposition, the In and Ga evaporation sources are turned off, and the Se evaporation source is kept on. After that, the substrate is cooled. When the substrate is at the set temperature, the Se evaporation source is turned off. At this time, the CIGS film can be obtained.

[0011] In the step 1, the step 2 and the step 3, when the evaporation source is in operation, the alkali metal ions are injected through the ion accelerator, and the energy of the ion injection is between 0-2 MeV.

[0012] As a preferred solution of the ion irradiation method for element doping of a flexible copper indium gallium selenide film described in the present invention, wherein: in the step one, the step two and the step three, the substrate is always in a rotating state to improve the uniformity of the film.

[0013] As a preferred scheme of the ion irradiation method for element doping of flexible copper indium gallium selenide film described in the present invention, wherein: when the alkali metal ions are injected in step one, step two and step three, it will be in a vacuum state, and the vacuum degree is 6-10Pa.

[0014] As a preferred embodiment of the ion irradiation method for element doping of a flexible copper indium gallium selenide film described in the present invention, when alkali metal ions are injected in step one, step two and step three, an electron gun is used to bombard the alkali metal elements in the ion accelerator irradiation source so that the elements are ionized to form alkali metals, and the ions are continuously accelerated from the irradiation source to be injected into the copper indium gallium selenide film under the action of an external electric field.

[0015] As a preferred solution of the ion irradiation method for element doping of a flexible copper indium gallium selenide film described in the present invention, the temperature set in the step 1 is 400°C.

[0016] As a preferred solution of the ion irradiation method for element doping of a flexible copper indium gallium selenide film described in the present invention, the deposition time in the step 1 is 40 minutes.

[0017] As a preferred solution of the ion irradiation method for element doping of a flexible copper indium gallium selenide film described in the present invention, the temperature set in the step 2 is 450°C.

[0018] As a preferred solution of the ion irradiation method for element doping of a flexible copper indium gallium selenide film described in the present invention, the temperature required in the step 2 is 550°C.

[0019] As a preferred solution of the ion irradiation method for element doping of a flexible copper indium gallium selenide film described in the present invention, wherein: the cooling rate of the substrate in the step three is 10° C. / min.

[0020] As a preferred solution of the ion irradiation method for element doping of a flexible copper indium gallium selenide film described in the present invention, the temperature set in the step three is 250°C.

[0021] Compared with existing technologies:

[0022] The present invention adopts a controllable particle implantation method and uses an adjustable ion accelerator with different ion energy distributions to implant alkali metal ions. The energy of the ion implantation is between 0-2MeV. Based on this, compared with the existing technical methods, the present invention can accurately control the amount and depth of ion implantation and the distribution of ions in the film, and can also implant multiple ions at the same time, so that the synergistic effect of alkali metal elements on the film quality and battery efficiency can be fully verified; in addition, combined with annealing during the ion implantation process, the distribution of the implanted ions can be made more uniform; thus, not only the film performance and uniformity can be improved, but also the device conversion efficiency can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the process flow of the present invention;

[0024] Figure 2 Schematic diagram of the quaternary evaporation CIGS thin film preparation equipment of the present invention;

[0025] Figure 3 This is a schematic diagram of ion irradiation of the present invention;

[0026] Figure 4 This is a schematic diagram of the American 2×1.7MV Tandem tandem electrostatic accelerator of the present invention. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0028] The present invention provides an ion irradiation method for element doping of a flexible copper indium gallium selenide film. Figure 1-Figure 4 , including the following specific steps:

[0029] Step 1: Keep the substrate at a set temperature, then turn on the In, Ga, and Se evaporation sources to deposit In, Ga, and Se on the substrate, wherein the set temperature is 400° C. and the deposition time is 40 minutes;

[0030] Step 2: turn off the In and Ga evaporation sources and raise the substrate temperature. When the substrate rises to the set temperature, turn on the Cu evaporation source and keep the substrate at the required temperature. The set temperature is 450°C and the required temperature is 550°C.

[0031] Step 3: When the substrate temperature drops, the Cu evaporation source is turned off, and the In and Ga evaporation sources are turned on. After 5 minutes of deposition, the In and Ga evaporation sources are turned off, and the Se evaporation source is kept on. After that, the substrate is cooled. After the substrate is at the set temperature, the Se evaporation source is turned off. At this time, the CIGS thin film can be obtained, wherein the cooling rate of the substrate is 10°C / min, and the set temperature is 250°C.

[0032] The evaporation source used in the above is a quaternary evaporation device, specifically Figure 2 As shown, the device has a total of five evaporation sources and can evaporate five elements at the same time.

[0033] In the step 1, the step 2 and the step 3, when the evaporation source is in operation, the alkali metal ions are injected through the ion accelerator, and the energy of the ion injection is between 0-2 MeV, wherein, Figure 4 As shown, the ion accelerator selected is a 2×1.7MV tandem electrostatic accelerator imported from the National Electrostatics Corporation (NEC) of the United States, model 5SDH-2. The equipment is equipped with a high-frequency charge exchange negative ion source and a sputtering negative ion source, which can accelerate some H-Au ions, and the beam intensity range is nA-μA; the equipment is mainly for high-energy ion implantation (MeV) and ion beam analysis measurement technology at high and low temperatures, including Rutherford backscattering and channeling analysis, elastic recoil analysis, nuclear reaction analysis, etc., providing reliable guarantee and sufficient machine time conditions for ion irradiation and ion beam analysis experiments.

[0034] In the step 1, the step 2 and the step 3, the substrate is always in a rotating state so as to improve the uniformity of the film.

[0035] When the alkali metal ions are injected in step 1, step 2 and step 3, they are in a vacuum state, and the vacuum degree is 6-10Pa; in addition, when the alkali metal ions are injected, the alkali metal elements in the ion accelerator radiation source are bombarded by an electron gun to ionize the elements to form alkali metals, and the ions are continuously accelerated from the radiation source to be injected into the copper indium gallium selenide film under the action of an external electric field, wherein not only the energy of the injected ions can be adjusted according to the size of the external electric field, but also the amount of the injected alkali metal elements can be controlled according to the intensity of the electron gun bombardment; in addition, Figure 3 As shown, the upper part is the ion source and the lower part is the copper indium gallium selenide film.

[0036] Although the present invention has been described above with reference to the embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the various features in the embodiments disclosed in the present invention may be used in combination with each other in any manner, and the fact that these combinations are not exhaustively described in this specification is only for the sake of omitting space and saving resources. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An ion irradiation method for element doping of a flexible copper indium gallium selenide film, characterized in that: The specific steps are as follows: Step 1: Keep the substrate at a set temperature, then turn on the In, Ga, and Se evaporation sources to deposit In, Ga, and Se on the substrate; Step 2: Turn off the In and Ga evaporation sources and increase the substrate temperature. When the substrate rises to the set temperature, turn on the Cu evaporation source and keep the substrate at the required temperature. Step 3: When the substrate temperature drops, the Cu evaporation source is turned off, and the In and Ga evaporation sources are turned on. After 5 minutes of deposition, the In and Ga evaporation sources are turned off, and the Se evaporation source is kept on. After that, the substrate is cooled. When the substrate is at the set temperature, the Se evaporation source is turned off. At this time, the CIGS film can be obtained. In the step 1, the step 2 and the step 3, when the evaporation source is in operation, the alkali metal ions are injected through the ion accelerator, and the energy of the ion injection is between 0-2 MeV.

2. The ion irradiation method for element doping of a flexible copper indium gallium selenide film according to claim 1, characterized in that: In the step 1, the step 2 and the step 3, the substrate is always in a rotating state so as to improve the uniformity of the film.

3. The ion irradiation method for element doping of a flexible copper indium gallium selenide film according to claim 1, characterized in that: When the alkali metal ions are injected in step 1, step 2 and step 3, the chamber is in a vacuum state with a vacuum degree of 6-10Pa.

4. The ion irradiation method for element doping of a flexible copper indium gallium selenide thin film according to claim 1, characterized in that: When alkali metal ion implantation is performed in step one, step two, and step three, the alkali metal elements in the ion accelerator radiation source are bombarded by an electron gun to ionize the elements to form alkali metals, and the ions are continuously accelerated from the radiation source and injected into the copper indium gallium selenide film under the action of an external electric field.

5. The ion irradiation method for element doping of a flexible copper indium gallium selenide thin film according to claim 1, characterized in that: The temperature set in step 1 is 400°C.

6. The ion irradiation method for element doping of a flexible copper indium gallium selenide thin film according to claim 1, characterized in that: The deposition time in step 1 is 40 min.

7. The ion irradiation method for element doping of a flexible copper indium gallium selenide thin film according to claim 1, characterized in that: The temperature set in step 2 is 450°C.

8. The ion irradiation method for element doping of a flexible copper indium gallium selenide thin film according to claim 1, characterized in that: The temperature required in step 2 is 550°C.

9. The ion irradiation method for element doping of a flexible copper indium gallium selenide thin film according to claim 1, characterized in that: The cooling rate of the substrate in step 3 is 10° C. / min.

10. The ion irradiation method for element doping of a flexible copper indium gallium selenide thin film according to claim 1, characterized in that: The temperature set in step 3 is 250°C.

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