Silver reflector-based electroluminescent device on silicon substrate
By integrating colloidal quantum dots on silicon substrates and introducing silver mirrors, the problem of low coupling efficiency of electroluminescent devices on silicon substrates is solved, and high-efficiency energy coupling is achieved, which significantly improves the application potential of silicon photonic chips.
Patent Information
- Application Number
- CN202420756822.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-12
- Publication Date
- 2024-12-17
- Estimated Expiration
- 2034-04-12
AI Technical Summary
The average coupling efficiency of existing quantum dot electroluminescent devices on silicon substrates is low, and it is impossible to effectively realize the on-chip light source, which limits the application potential of silicon photonic chips.
Design an electroluminescent device on silicon substrate based on silver mirrors. By introducing silver mirrors into the silicon nitride waveguide layer and integrating colloidal quantum dots on the silicon substrate, the silver mirror is used as a gain structure to improve the light source and High-efficiency energy coupling between silicon nitride waveguide layers.
It significantly improves the average coupling efficiency of electroluminescent devices on silicon substrates and improves the transmission efficiency of light energy, so that the light energy coupled into the silicon nitride waveguide layer increases from 0.8% to 9.39% or 9.76%, greatly improving silicon photonics Application potential of chips.
Smart Images
Figure CN222192962U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of light sources on silicon substrates, in particular to an electroluminescent device on silicon substrates based on silver reflectors. Background Art
[0002] Silicon photonic chips have broad application prospects. In the field of sensors, silicon photonic chips can be used to measure and detect various physical and chemical parameters, such as gas sensors, biosensors and environmental sensors, promoting the development of precise measurement and real-time monitoring technology. Therefore, the development of highly efficient coupled silicon photonic chips is of great practical significance.
[0003] In order to achieve high-efficiency coupling of silicon photonic chips, one of the main challenges is the lack of an on-chip light source. Currently produced silicon photonic chips usually use edge coupling or grating coupling methods to couple external lasers. Although the energy of external light sources can be coupled through edge coupling or grating coupling, and the coupling efficiency has been improved, the lack of an on-chip light source limits the potential applications of these chips. However, since silicon is an indirect bandgap semiconductor, its own luminescence efficiency is very low and it cannot be directly used to prepare on-chip light sources.
[0004] The average coupling efficiency of existing quantum dot electroluminescent devices on silicon substrates is low. When light enters the waveguide and oscillates steadily, the stably transmitted energy accounts for only 0.8% of the total energy of the light source. Utility Model Content
[0005] The technical problem to be solved by the utility model is to provide an electroluminescent device on a silicon substrate based on a silver reflector in view of at least one defect of the above-mentioned background technology.
[0006] The technical solution adopted by the utility model to solve the technical problem is: to provide an electroluminescent device on a silicon substrate based on a silver reflector, which includes a silicon substrate, a first transparent insulating layer, a silicon nitride waveguide layer, an electron transport layer, two first electrode layers, a silver reflector, a quantum dot layer, a hole transport layer, a second electrode layer, and a second transparent insulating layer;
[0007] The first transparent insulating layer is disposed on the silicon substrate;
[0008] The silicon nitride waveguide layer and the electron transport layer are respectively arranged on the first transparent insulating layer, and the electron transport layer covers the silicon nitride waveguide layer;
[0009] The two first electrode layers are respectively arranged on the electron transport layer, and the two first electrode layers are respectively located on two opposite sides of the silicon nitride waveguide layer;
[0010] The silver reflector is embedded in the silicon nitride waveguide layer, and a preset angle α is formed between the silver reflector and the cross section of the silicon nitride waveguide layer;
[0011] The quantum dot layer is disposed on the electron transport layer;
[0012] The hole transport layer is disposed on the quantum dot layer;
[0013] The second electrode layer is disposed on the hole transport layer;
[0014] The second transparent insulating layer is disposed between the electron transport layer and the second electrode layer, and the quantum dot layer and the hole transport layer are surrounded by the second transparent insulating layer;
[0015] The second transparent insulating layer is provided with two second grooves, and the two first electrode layers are exposed through the two second grooves respectively.
[0016] Preferably, it also includes a third transparent insulating layer and a silver reflective layer between the silicon substrate and the first transparent insulating layer; the third transparent insulating layer is arranged between the silicon substrate and the silver reflective layer, and the silver reflective layer is arranged between the third transparent insulating layer and the first transparent insulating layer.
[0017] Preferably, the minimum distance b between the silver reflective layer and the lower surface of the silicon nitride waveguide layer is 500 nm.
[0018] Preferably, the preset angle is 40° to 45°; and the thickness of the silver reflector is 50 to 150 nm.
[0019] Preferably, the thickness of the silicon nitride waveguide layer is 200-400 nm;
[0020] Preferably, the width of the silicon nitride waveguide layer is 500-1500 nm;
[0021] Preferably, the thickness of the quantum dot layer is 5 to 50 nm;
[0022] Preferably, the hole transport layer has a thickness of 550-700 nm.
[0023] Preferably, along the width direction of the silicon nitride waveguide layer, the central axis of each first electrode layer and the central axis of the quantum dot layer are collinear.
[0024] The utility model has at least the following beneficial effects: the utility model integrates colloidal quantum dots on a silicon substrate and introduces a silver reflector into a silicon nitride waveguide layer, and uses the silver reflector as a gain structure for increasing the average coupling efficiency, thereby achieving efficient energy coupling between a light source and a silicon nitride waveguide layer. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] In order to more clearly illustrate the technical solution of the utility model, the utility model will be further described below in conjunction with the accompanying drawings and embodiments, in which:
[0026] Figure 1 It is a schematic diagram of the three-dimensional structure of the electroluminescent device on a silicon substrate based on a silver reflector according to the first embodiment of the utility model;
[0027] Figure 2 yes Figure 1 A schematic diagram of the enlarged structure of part A;
[0028] Figure 3 yes Figure 1 A schematic diagram of the longitudinal cross-sectional structure of the electroluminescent device on a silicon substrate based on a silver reflector in a first direction is shown;
[0029] Figure 4 yes Figure 1 A schematic diagram of the longitudinal cross-sectional structure of the electroluminescent device on a silicon substrate based on a silver reflector in the second direction;
[0030] Figure 5 This is a waveguide energy transmission diagram of an electroluminescent device on a silicon substrate based on a silver reflector according to the first embodiment of the utility model;
[0031] Figure 6 is a cross-sectional energy comparison diagram between the electroluminescent device on a silicon substrate before the introduction of the silver reflector and the electroluminescent device on a silicon substrate based on the silver reflector according to the first embodiment of the utility model;
[0032] Figure 7 is a comparison diagram of waveguide energy transmission between an electroluminescent device on a silicon substrate before the introduction of a silver reflector and an electroluminescent device on a silicon substrate based on a silver reflector according to the first embodiment of the utility model;
[0033] Figure 8 This is an energy distribution diagram of an electroluminescent device on a silicon substrate based on a silver reflector confined in a silicon nitride waveguide layer according to the first embodiment of the utility model;
[0034] Fig. 9 It is a schematic diagram of the three-dimensional structure of an electroluminescent device on a silicon substrate based on a silver reflector according to the second embodiment of the utility model;
[0035] Fig.10 yes Fig. 9 A schematic diagram of the longitudinal cross-sectional structure of the electroluminescent device on a silicon substrate based on a silver reflector in a first direction is shown;
[0036] Fig.11 yes Fig. 9A schematic diagram of the longitudinal cross-sectional structure of the electroluminescent device on a silicon substrate based on a silver reflector in the second direction;
[0037] Fig.12 It is a cross-sectional energy comparison diagram between the electroluminescent device on a silicon substrate based on a silver reflector of the first embodiment of the utility model and the electroluminescent device on a silicon substrate based on a silver reflector of the second embodiment;
[0038] Fig.13 It is a comparison diagram of waveguide energy transmission between the electroluminescent device on a silicon substrate based on a silver reflector of the first embodiment of the utility model and the electroluminescent device on a silicon substrate based on a silver reflector of the second embodiment;
[0039] Fig.14 This is an energy distribution diagram of an electroluminescent device on a silicon substrate based on a silver reflector confined in a silicon nitride waveguide layer according to the second embodiment of the utility model;
[0040] Fig.15 It is a schematic diagram of the preparation process of the electroluminescent device on a silicon substrate based on a silver reflector in some embodiments of the utility model. DETAILED DESCRIPTION
[0041] In order to have a clearer understanding of the technical features, purposes and effects of the utility model, the specific implementation methods of the utility model are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that when an element is referred to as being "on" or "under" another element, the element can be "directly" or "indirectly" located on the other element, or there may also be one or more intermediate elements. The terms "first", "second", "third", etc. are only for the convenience of describing the present technical solution, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined as "first", "second", "third", etc. can explicitly or implicitly include one or more of the features. For those of ordinary skill in the art, the specific meanings of the above terms in the utility model can be understood according to the specific circumstances.
[0042] See also Figures 1 to 4 , Figure 1 It is a schematic diagram of the three-dimensional structure of the electroluminescent device on a silicon substrate based on a silver reflector (hereinafter referred to as the device) of the first embodiment of the utility model; Figure 2 yes Figure 1 The enlarged structural diagram of part A in the middle; Figure 3 yes Figure 1 The longitudinal cross-sectional structure diagram of the device shown in the first direction, Figure 4 yes Figure 1 The longitudinal cross-sectional structure diagram of the device shown in the second direction, wherein the first direction and the second direction are perpendicular to each other. Figures 1 to 4As shown, the device includes a silicon substrate 1, a first transparent insulating layer 21, a silicon nitride waveguide layer 3, an electron transport layer 41, two first electrode layers 51, a silver reflector 6, a quantum dot layer 7, a hole transport layer 42, a second electrode layer 52, and a second transparent insulating layer 23.
[0043] The first transparent insulating layer 21 is disposed on the silicon substrate 1. The silicon nitride (SiN) waveguide layer 3 and the electron transport layer 41 are respectively disposed on the first transparent insulating layer 21, and the electron transport layer 41 covers the silicon nitride waveguide layer 3. Two first electrode layers 51 are respectively disposed on the electron transport layer 41, and the two first electrode layers 51 are respectively located on opposite sides of the silicon nitride waveguide layer 3. The silver reflector 6 is embedded in the silicon nitride waveguide layer 3. The quantum dot layer 7 is disposed on the electron transport layer 41. The hole transport layer 42 is disposed on the quantum dot layer 7. The second electrode layer 52 is disposed on the hole transport layer 42. The quantum dot layer 7 and the hole transport layer 42 serve as QLEDs (Quantum Dot Light Emitting Diodes).
[0044] The quantum dot layer 7 and the hole transport layer 42 are surrounded by the second transparent insulating layer 23. The second transparent insulating layer 23 provides a molding basis for the quantum dot layer 7, the hole transport layer 42 and the second electrode layer 52. A first groove 231 and two second grooves 232 are provided on the second transparent insulating layer 23. The first groove 231 is located at the center of the second transparent insulating layer 23. Along the width direction of the silicon nitride waveguide layer 3, the two second grooves 232 are symmetrically arranged on opposite sides of the first groove 231, and along the width direction of the silicon nitride waveguide layer 3, the central axis of the first groove 231 and each second groove 232 are collinear. The two first electrode layers 51 are exposed through the two second grooves 232 respectively. The quantum dot layer 7 and the hole transport layer 42 are both arranged in the first groove 231. The second electrode layer 52 is covered on the first groove 231.
[0045] like Figures 1 to 4 In the first embodiment shown, the cross-sectional area of the silicon nitride waveguide layer 3 is smaller than the cross-sectional area of the first transparent insulating layer 21. Figure 1 In the illustrated embodiment, the silicon nitride waveguide layer 3 is in the shape of a long strip. In addition, along the horizontal direction, two opposite edges of the silicon nitride waveguide layer 3 are aligned one by one with two opposite edges of the first transparent insulating layer 21. It should be noted that the "cross section" of a component refers to its cross section along the horizontal direction, and the horizontal direction is parallel to the placement surface of the device, and the placement surface of the device refers to the placement surface of the device in a naturally placed state.
[0046] like Figures 1 to 3In the first embodiment shown, the cross-section of each first electrode layer 51, the cross-section of the quantum dot layer 7, the cross-section of the hole transport layer 42, and the cross-section of the second electrode layer 52 are all square. Moreover, the cross-sectional areas of each first electrode layer 51, the quantum dot layer 7, the hole transport layer 42, and the second electrode layer 52 are equal. Along the width direction of the silicon nitride waveguide layer 3, the width w1 of the silicon nitride waveguide layer 3, the width w2 of the quantum dot layer 7, and the width w3 of each first electrode layer 51 are equal, that is, w1=w2=w3. However, in other embodiments, w1, w2, and w3 may also be unequal. In particular, along the width direction of the silicon nitride waveguide layer 3, the central axis of each first electrode layer 51 and the central axis of the quantum dot layer 7 are collinear. The two first electrode layers 51 are symmetrically arranged on both sides of the quantum dot layer 7, so that the carrier transport can be more uniform and the device response speed can be faster.
[0047] The utility model simulates the structural parameters of the device through light wave electromagnetic field modeling and simulation, and arranges the first electrode layer 51, the electron transport layer 41, the hole transport layer 42, and the second electrode layer 52 on the opposite sides of the quantum dot layer 7, that is, the colloidal quantum dots are integrated in the electroluminescent device on the silicon substrate, and the light source generated at the quantum dot layer 7 is coupled with the silicon nitride waveguide layer 3, so that the energy coupled into the silicon nitride waveguide layer 3 is mostly confined in the silicon nitride waveguide layer 3, thereby increasing the light output rate.
[0048] On this basis, the inventors found that before entering the silicon nitride waveguide layer 3, part of the emitted light was not coupled into the silicon nitride waveguide layer 3, resulting in energy loss, while part of the emitted light after being coupled into the silicon nitride waveguide layer 3 propagated toward the end opposite to the energy output end, which greatly reduced the effective propagation light energy coupled into the silicon nitride waveguide layer 3. Both of these factors reduced the average coupling efficiency of the device.
[0049] The device of the utility model can solve the above two technical problems.
[0050] First, in order to solve the problem of energy loss caused by part of the outgoing light after coupling into the silicon nitride waveguide layer 3 propagating toward the end opposite to the energy output end, the first embodiment of the utility model introduces a silver reflector 6 with a specific inclination angle corresponding to the incident light of a specific wavelength into the silicon nitride waveguide layer 3 to reflect the light that is coupled into the silicon nitride waveguide layer 3 and propagates in the direction opposite to the energy output end. That is, the silver reflector 6 serves as a gain structure for increasing the average coupling efficiency.
[0051] Please also read Figures 5 to 7 ,exist Figures 5 to 7In the corresponding first embodiment, the first transparent insulating layer 21 is made of silicon dioxide (SiO2), the electron transport layer 41 is made of zinc oxide (ZnO), and the quantum dot layer 7 and the hole transport layer 42 are marked as QLED (Quantum Dot Light Emitting Diodes) in the figure.
[0052] See also Figure 5 , Figure 5 The waveguide energy transmission diagram of the device of the first embodiment of the utility model is shown. Figure 5 It can be seen that the light originally transmitted in the opposite direction to the energy output end is greatly reflected back to the energy output end (right end in the figure), which greatly improves the transmission efficiency of the energy output end.
[0053] See also Figure 6 , Figure 6 The cross-sectional energy comparison diagram between the electroluminescent device on a silicon substrate before the introduction of the silver reflector 6 and the device of the first embodiment of the utility model is shown. The left side is the cross-sectional energy diagram of the electroluminescent device on a silicon substrate before the introduction of the silver reflector 6 at a distance of 50 μm from the center of the waveguide, and the right side is the cross-sectional energy diagram of the device of the first embodiment of the utility model (with the introduction of the silver reflector 6) at a distance of 50 μm from the center of the waveguide. Figure 6 It can be seen intuitively that after the silver reflector 6 is introduced, the concentrated energy below the QLED (at the silicon nitride waveguide layer 3) increases significantly, and the maximum value of the light energy concentrated on the right is almost twice that of the left, indicating that the light is effectively reflected back to the energy output end, thereby improving the transmission efficiency of the energy output end.
[0054] See also Figure 7 , Figure 7 The figure shows a comparison of waveguide energy transmission between the electroluminescent device on a silicon substrate before the introduction of the silver reflector 6 and the device of the first embodiment of the utility model. The left side is the waveguide energy transmission diagram of the electroluminescent device on a silicon substrate before the introduction of the silver reflector 6, and the right side is the waveguide energy transmission diagram of the device of the first embodiment of the utility model (with the introduction of the silver reflector 6). Figure 7 As shown on the left, inside the silicon nitride waveguide layer 3 of the electroluminescent device on the silicon substrate before the Ag reflector is introduced, light propagates along both ends; Figure 7 As shown on the right side, after the introduction of the Ag reflector, there is almost no light at the left end of the silicon nitride waveguide layer 3, which means that after the introduction of the Ag reflector, the light at the left end of the silicon nitride waveguide layer 3 is greatly reflected back to the right end (energy output end), which means that the light is effectively reflected back to the energy output end, thereby improving the transmission efficiency of the energy output end.
[0055] See also Figure 8 , Figure 8The energy distribution diagram of the device confined in the silicon nitride waveguide layer 3 of the first embodiment of the utility model is shown. In the diagram, the horizontal axis waveguide length refers to the length position on the silicon nitride waveguide layer 3. Figure 7 It can be seen that after the silver reflector 6 is introduced, the coupled light of the device is stabilized by oscillation, and its average transmission efficiency can reach 9.39% at a distance of 50 μm from the center of the waveguide, which is roughly 11 times the average coupling efficiency (0.8%) of the existing related devices mentioned in the background technology, significantly improving the average transmission efficiency of the waveguide of the electroluminescent device on the silicon substrate.
[0056] Secondly, in order to solve the problem of energy loss caused by part of the emitted light not being coupled into the silicon nitride waveguide layer 3, the device of the second embodiment of the utility model is different from the first embodiment in that a silver reflection layer 8 is introduced between the silicon substrate 1 and the first transparent insulating layer 21, and the silver reflection layer 8 is used to reflect the light that is not coupled into the silicon nitride waveguide layer 3. Specifically, the device also includes a third transparent insulating layer 22 and a silver reflection layer 8 between the silicon substrate 1 and the first transparent insulating layer 21. The third transparent insulating layer 22 is arranged between the silicon substrate 1 and the silver reflection layer 8, and the silver reflection layer 8 is arranged between the third transparent insulating layer 22 and the first transparent insulating layer 21.
[0057] Please also read Figures 9 to 14 , Figures 9 to 11 The device structure diagram of the second embodiment of the utility model is shown. Figure 12 to Figure 14 1 is a schematic diagram of the technical effect corresponding to the second embodiment. In this embodiment, the first transparent insulating layer 21 is made of silicon dioxide (SiO2), the electron transport layer 41 is made of zinc oxide (ZnO), and the quantum dot layer 7 and the hole transport layer 42 are marked as QLED (Quantum Dot Light Emitting Diodes) in the figure.
[0058] See also Fig.12 , Fig.12 The cross-sectional energy comparison diagram between the device of the first embodiment and the device of the second embodiment of the utility model is shown. The left side is the cross-sectional energy diagram of the device of the first embodiment (only silver reflector 6, no silver reflective layer 8) at a distance of 50 μm from the center of the waveguide, and the right side is the cross-sectional energy diagram of the device of the second embodiment of the utility model (with both silver reflector 6 and silver reflective layer 8) at a distance of 50 μm from the center of the waveguide. Fig.12 It can be seen intuitively that after the silver reflective layer 8 is introduced, the energy gathered at the silicon nitride (SiN) waveguide layer increases significantly, indicating that the light is effectively reflected back to the silicon nitride waveguide layer 3 by the silver reflective layer 8, further improving the average coupling efficiency.
[0059] See also Fig.13 , Fig.13The figure shows a comparison of waveguide energy transmission between the device of the first embodiment and the device of the second embodiment of the utility model. The left side is the waveguide energy transmission diagram of the device of the first embodiment (only silver reflector 6, no silver reflective layer 8), and the right side is the waveguide energy transmission diagram of the device of the second embodiment (with both silver reflector 6 and silver reflective layer 8). Fig.13 It can be seen that the light that escapes to SiO2 (transparent insulating layer) and is not coupled into the silicon nitride waveguide layer 3 is reflected back into the silicon nitride waveguide layer 3 by the silver reflective layer 8, thereby improving the transmission efficiency of the energy output end.
[0060] See also Fig.14 , Fig.14 The energy distribution diagram of the device confined in the silicon nitride waveguide layer 3 of the second embodiment of the utility model is shown. In the diagram, the horizontal axis waveguide length refers to the length position on the silicon nitride waveguide layer 3. Fig.14 It can be seen that after the silver reflective layer 8 is introduced, the coupled light of the device is stabilized by oscillation, and its average transmission efficiency can reach 9.76% at a distance of 50 μm from the center of the waveguide, which is 0.37% higher than that of the first embodiment, and is roughly 12 times the average coupling efficiency (0.8%) of the existing related devices mentioned in the background technology, which significantly improves the average transmission efficiency of the waveguide of the electroluminescent device on the silicon substrate.
[0061] The second embodiment of the utility model utilizes a silver reflector and a silver reflective layer as two gain structures for increasing light coupling efficiency, thereby realizing efficient energy coupling between the light source and the silicon nitride waveguide layer.
[0062] Furthermore, the influence of the preset angle α between the silver reflector 6 and the cross section of the silicon nitride waveguide layer 3 and the minimum distance b between the silver reflector 8 and the lower surface of the silicon nitride waveguide layer 3 on the transmission efficiency is studied, and the average transmission efficiency values of the three dipole oscillation directions (0°, 90°, 0°; 0°, 0°, 90°; 0°, 90°, 90°) are taken, and the preset angle α and the minimum distance b corresponding to the maximum average transmission efficiency are selected. The lower surface of the silicon nitride waveguide layer 3 refers to the surface facing the silver reflector 8. In particular, the preset angle α formed between the silver reflector 6 and the cross section of the silicon nitride waveguide layer 3 can be 30° to 50°, and the thickness of the silver reflector 6 can be 50 to 150 nm, which can be adapted to light with a wavelength of 630 to 660 nm. That is, when the preset angle is 40-45° and the thickness of the silver reflector 6 is 50-150 nm, a better coupling efficiency can be achieved for light with a wavelength of 630-660 nm. For example, when light with a wavelength of 650 nm is introduced, the preset angle can be configured as 45° and the thickness of the silver reflector 6 can be configured as 100 nm, so as to achieve the best coupling efficiency. The minimum distance b between the silver reflective layer 8 and the lower surface of the silicon nitride waveguide layer 3 can be 500 nm.
[0063] Furthermore, in order to confine most of the energy coupled into the waveguide in the waveguide and obtain better coupling efficiency, the thickness of the silicon nitride waveguide layer 3 can be set to 200-400nm, the width of the silicon nitride waveguide layer 3 can be set to 500-1500nm, the thickness of the quantum dot layer 7 can be set to 5-50nm, and the thickness of the hole transport layer 42 can be set to 550-700nm.
[0064] Furthermore, if Figure 1 to Figure 2 In the first embodiment shown, the cross-sectional area of the second groove 232 is equal to the cross-sectional area of each first electrode layer 51, and is also equal to the cross-sectional area of the first groove 231. Along the width direction of the silicon nitride waveguide layer 3, the width of the first groove 231 and the width of each second groove 232 may be equal to the width w1 of the silicon nitride waveguide layer 3.
[0065] The materials of each structural layer can be set as follows: the material of the first transparent insulating layer 21 / the second transparent insulating layer 23 / the third transparent insulating layer 22 can include one of silicon dioxide, polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), polystyrene (PS), and polycarbonate (PC). The material of the first electrode layer 51 can include at least one of IZO (indium zinc oxide) and indium tin oxide (ITO). The material of the second electrode layer 52 can include at least one of aluminum, silver, and silver nanowires. That is, the first electrode layer 51 and the second electrode layer 52 can be a single electrode layer (only one electrode material) or a composite electrode layer (having two or more electrode materials). The material of the quantum dot layer 7 can include one of lead sulfide (PbS), lead selenide (PbSe), indium phosphide (InP), cadmium selenide (CdSe), and cadmium sulfide (CdS). The material of the electron transport layer 41 may include at least one of 1,3,5-tri(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi), tin dioxide (SnO2), and zinc oxide (ZnO). The material of the hole transport layer 42 may include at least one of 4,4',4'-tri(carbazole-9-yl)triphenylamine (TCTA), C 29 H 31 C l2 At least one of N3O2 (NPB), 12-hexaazatriphenylene (HAT-CN), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TPD), and polystyrene sulfonate (PEDOT:PSS).
[0066] Technical features not mentioned in any of the above embodiments can be set with reference to other embodiments and will not be described in detail here.
[0067] Please check Fig.15 The following is a specific process of a method for preparing an electroluminescent device on a silicon substrate based on a silver reflector according to an embodiment of the present invention:
[0068] S11, when the high energy electron beam acceleration voltage is 10 kV, the electron beam current is about 10-100 mA, the beam spot diameter is about 3 mm, and the background vacuum of the evaporation chamber is 8×10 -4 Pa, under the condition that the distance between the substrate and the crucible is 8 cm, a silicon dioxide (SiO2) film with a thickness of 300 nm is evaporated, and the silicon dioxide film serves as the third transparent insulating layer 22.
[0069] S12. Under the conditions of a high-energy electron beam acceleration voltage of 10 kV and an electron beam current of 0.2 A, a silver reflective layer 8 with a thickness of 200 nm is evaporated on the third transparent insulating layer 22.
[0070] S13, when the high energy electron beam acceleration voltage is 10 kV, the electron beam current is about 10-100 mA, the beam spot diameter is about 3 mm, and the background vacuum of the evaporation chamber is 8×10 -4 Pa, and under the condition that the distance between the substrate and the crucible is 8 cm, a silicon dioxide film with a thickness of 500 nm is evaporated on the silver reflective layer 8, and the silicon dioxide film serves as the first transparent insulating layer 21.
[0071] S21. Under the conditions of a temperature of 450°C, a volume ratio of NH3 and SiH4 of 8:1, a total gas flow of 4320 sccm, a pressure of 170 Pa, and a precipitation rate of 6.25 nm / min, a layer of 300 nm thick silicon nitride (SiN) film is deposited on the first transparent insulating layer 21. The silicon nitride film serves as the silicon nitride base layer 31.
[0072] S22, under the conditions of low speed of 500r / min for 6s, high speed of 4000r / min for 30s, pre-baking temperature of 95°C for 3min, a layer of photoresist (model AZ4620) with a thickness of 5.6μm is spin-coated on the silicon nitride base layer 31. Then, under the conditions of exposure dose of 60mJ, volume ratio of developer of V(AZ400K) : V(H2O) = 1:3, development time of 60s, post-baking temperature of 115°C, and exposure time of 10min, exposure and development are completed. Finally, an etching solution with a volume ratio of V(HF)∶V(NH4F)∶V(CH3COOH)=1∶5∶1 was prepared at room temperature and placed in a plastic container. During the etching process, the plastic container was heated by a constant temperature magnetic stirrer with a speed of 650r / min. At a temperature of 60°C and an etching rate of 109.5nm / min, a long silicon nitride waveguide layer 3 with a cross-sectional size of 300×1000nm was obtained.
[0073] S31, using a Faraday cage with a mesh diameter of 38μm, a size diameter of 50mm, and a height of 8mm, the device after the above step S22 is placed inside the Faraday cage at an angle of 45°, and the size of the mask opening is 0.1411μm. First, the upper electrode RF power is 1300W, the lower electrode RF power is 0W, the time is 1s, the C4F8 volume flow rate is 200mL / min, and the SF6 is 0mL / min to complete the passivation. Then the upper electrode RF power is 1600W, the lower electrode RF power is 50W, the time is 0.1s, the C4F8 volume flow rate is 0mL / min, and the SF6 is 200mL / min to complete the etching, and the inclined groove 32 with an angle of 45° and a thickness of 100nm is obliquely etched in the center of the silicon nitride waveguide layer 3.
[0074] S32, when the high energy electron beam acceleration voltage is 10 kV, the electron beam current is 0.2 A, the distance between the substrate and the crucible is 8 cm, the beam spot diameter is about 3 mm, and the background vacuum of the evaporation chamber is 8×10- 4 Under the condition of Pa, silver is evaporated at the opening of the inclined groove 32 through a light shield and a mask to form a silver reflector 6 with an inclination angle of 45° and a thickness of 100 nm in the center of the silicon nitride waveguide layer 3.
[0075] S4, coating a 10 nm thick polycrystalline zinc oxide (ZnO) layer on the silicon nitride waveguide layer 3, the zinc oxide layer serving as the electron transport layer 41. The zinc oxide layer covers the silicon nitride waveguide layer 3 and the first transparent insulating layer 21 at the same time.
[0076] S5, when the high energy electron beam acceleration voltage is 10 kV, the electron beam current is 25 mA, the distance between the substrate and the crucible is 8 cm, the beam spot diameter is about 3 mm, and the background vacuum of the evaporation chamber is 8×10- 4 Under the condition of 1000 Pa, two Ti electrodes with a thickness of 20 nm are simultaneously deposited on the left and right sides of the length direction of the silicon nitride waveguide layer 3. Then, under the same conditions, the electron beam current is adjusted to 12 mA, and a metal Au electrode with a thickness of 100 nm is deposited on the surface of each metal Ti electrode. Under the same conditions, the electron beam current is adjusted to 25 mA, and a Ti electrode with a thickness of 20 nm is deposited on the surface of each metal Au electrode. Finally, a Ti / Au composite electrode is formed on the left and right sides of the length direction of the silicon nitride waveguide layer 3, and the composite electrode serves as the first electrode layer 51.
[0077] S61, when the high energy electron beam acceleration voltage is 10 kV, the electron beam current is about 10-100 mA, the beam spot diameter is about 3 mm, and the background vacuum of the evaporation chamber is 8×10- 4Pa, and the distance between the substrate and the crucible is 8 cm, a 930 nm thick silicon dioxide film is evaporated, and the silicon dioxide film serves as the second transparent insulating layer 23, covering the electron transport layer 41 and the two first electrode layers 51. In addition, the silicon dioxide film protrudes a portion relative to other regions in the first region 233 corresponding to the silicon nitride waveguide layer 3 and the second region 234 corresponding to the two first electrode layers 51, and the upper surface of the silicon dioxide film is an uneven surface.
[0078] S62, adopt positive photoresist (Shipley, S1818, USA) to be ICPE of mask to carry out patterned etching on the upper surface of silicon dioxide film. Specifically, a layer of positive photoresist is plated on the upper surface of the second transparent insulating layer 23, and then the pattern is transferred to the photoresist from the mask by development, and then development and drying are carried out. Finally, the device with corresponding pattern photoresist on the surface is put into the vacuum chamber of the etcher for etching, and each gas ratio and gas flow rate are CHF3-200sccm, Ar-20sccm, O2-5sccm, upper radio frequency power RF1 is 700W, and lower radio frequency power RF2 is 200W, and silicon dioxide film is carried out patterned processing, and the first area 233 and the second area 234 on the silicon dioxide film are etched, so that the upper surface of silicon dioxide film forms a smooth surface.
[0079] S7, patterned etching is performed on the upper surface of the silicon dioxide film using ICPE with a positive photoresist (Shipley, S1818, USA) as a mask. Specifically, a layer of positive photoresist is plated on the second transparent insulating layer 23, and then the pattern is transferred from the mask to the photoresist by development, and then developed and dried. Finally, the device with the corresponding pattern photoresist on the surface is placed in the vacuum chamber of the etcher for etching. The gas ratio and gas flow rate are: CHF3-200sccm, Ar-20sccm, O2-5sccm, the upper radio frequency power RF1 is 700W, and the lower radio frequency power RF2 is 200W. A first groove 231 is formed in the middle of the upper surface of the silicon dioxide film, and a second groove 232 is formed corresponding to the position of the first electrode layer 51. The two first electrode layers 51 (Ti / Au composite electrodes) are exposed through the second groove 232 to form an electrical interconnection. The electron transport layer 41 (zinc oxide) is exposed through the first groove 231.
[0080] S8, dispersing a quantum dot solution of cadmium selenide (CdSe) and cadmium sulfide (CdS) in toluene to form a 2 mg / mL quantum dot ink, and then inkjet printing the quantum dot ink into the first groove 231 of the silicon nitride waveguide layer 3.
[0081] S81. Place the entire device obtained in step S8 on a hot plate at 100° C. for annealing for 10 minutes.
[0082] S9. In the first groove 231, a 70nm thick TCTA layer, a 500nm thick NPB layer and a 30nm thick HAT-CN layer are formed in sequence above the quantum dot layer 7 by evaporation. The TCTA layer, the NPB layer and the HAT-CN layer together serve as a hole transport layer 42 for optimizing energy band alignment and hole transport and injection.
[0083] S10, at a high-energy electron beam acceleration voltage of 9Kv, an electron beam current of 0.2A, a distance between the substrate and the crucible of 8cm, a beam spot diameter of about 3mm, and a background vacuum of 2.6×10- 4 Pa, a metal aluminum layer with a thickness of 300 nm is evaporated on the second transparent insulating layer 23 at a position corresponding to the first groove 231 . The metal aluminum layer serves as the second electrode layer 52 to cover the hole transport layer 42 .
[0084] It can be understood that the above embodiments only express the preferred implementation methods of the utility model, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the patent scope of the utility model. It should be pointed out that, for ordinary technicians in this field, without departing from the concept of the utility model, the above-mentioned technical features can be freely combined, and several deformations and improvements can be made, which all belong to the protection scope of the utility model. Therefore, all equivalent changes and modifications made to the scope of the claims of the utility model should fall within the scope of the claims of the utility model.
Claims
1. An electroluminescent device on a silicon substrate based on a silver reflector, characterized in that: It comprises a silicon substrate (1), a first transparent insulating layer (21), a silicon nitride waveguide layer (3), an electron transport layer (41), two first electrode layers (51), a silver reflector (6), a quantum dot layer (7), a hole transport layer (42), a second electrode layer (52), and a second transparent insulating layer (23); The first transparent insulating layer (21) is arranged on the silicon substrate (1); The silicon nitride waveguide layer (3) and the electron transport layer (41) are respectively arranged on the first transparent insulating layer (21), and the electron transport layer (41) covers the silicon nitride waveguide layer (3); The two first electrode layers (51) are respectively arranged on the electron transport layer (41), and the two first electrode layers (51) are respectively located on two opposite sides of the silicon nitride waveguide layer (3); The silver reflector (6) is embedded in the silicon nitride waveguide layer (3), and a preset angle α is formed between the silver reflector (6) and the cross section of the silicon nitride waveguide layer (3); The quantum dot layer (7) is arranged on the electron transport layer (41); The hole transport layer (42) is arranged on the quantum dot layer (7); The second electrode layer (52) is arranged on the hole transport layer (42); The second transparent insulating layer (23) is arranged between the electron transport layer (41) and the second electrode layer (52), and the quantum dot layer (7) and the hole transport layer (42) are surrounded by the second transparent insulating layer (23); Two second grooves (232) are provided on the second transparent insulating layer (23), and the two first electrode layers (51) are exposed through the two second grooves (232) respectively.
2. The electroluminescent device on a silicon substrate based on a silver reflector according to claim 1, characterized in that: It also comprises a third transparent insulating layer (22) and a silver reflective layer (8) between the silicon substrate (1) and the first transparent insulating layer (21); the third transparent insulating layer (22) is arranged between the silicon substrate (1) and the silver reflective layer (8), and the silver reflective layer (8) is arranged between the third transparent insulating layer (22) and the first transparent insulating layer (21).
3. The electroluminescent device on a silicon substrate based on a silver reflector according to claim 2, characterized in that: The minimum distance b between the silver reflective layer (8) and the lower surface of the silicon nitride waveguide layer (3) is 500 nm.
4. The electroluminescent device on a silicon substrate based on a silver reflector according to claim 1, characterized in that: The preset angle is 30° to 50°; the thickness of the silver reflector (6) is 50 to 150 nm.
5. The electroluminescent device on a silicon substrate based on a silver reflector according to claim 1, characterized in that: The thickness of the silicon nitride waveguide layer (3) is 200-400 nm.
6. The electroluminescent device on a silicon substrate based on a silver reflector according to claim 1, characterized in that: The width of the silicon nitride waveguide layer (3) is 500-1500 nm.
7. The electroluminescent device on a silicon substrate based on a silver reflector according to claim 1, characterized in that: The thickness of the quantum dot layer (7) is 5 to 50 nm.
8. The electroluminescent device on a silicon substrate based on a silver reflector according to claim 1, characterized in that: The thickness of the hole transport layer (42) is 550-700 nm.
9. The electroluminescent device on a silicon substrate based on a silver reflector according to claim 1, characterized in that: Along the width direction of the silicon nitride waveguide layer (3), the central axis of each first electrode layer (51) and the central axis of the quantum dot layer (7) are collinear.
10. The electroluminescent device on a silicon substrate based on a silver reflector according to claim 1, characterized in that: The cross-sectional area of the silicon nitride waveguide layer (3) is smaller than the cross-sectional area of the first transparent insulating layer (21), and along the horizontal direction, two opposite edges of the silicon nitride waveguide layer (3) are aligned one-to-one with two opposite edges of the first transparent insulating layer (21).