TWI415281B - Solar cell device - Google Patents

Abstract

A solar cell device includes a P-type amorphous silicon layer, an N-type micro-crystalline silicon layer, an N-type single crystal silicon layer, an intrinsic amorphous silicon layer, and an intrinsic micro-crystalline silicon layer. The N-type single crystal silicon layer is disposed between the P-type amorphous silicon layer and the N-type micro-crystalline silicon layer. The intrinsic amorphous silicon layer is disposed between the N-type single crystal silicon layer and the P-type amorphous silicon layer. The intrinsic micro-crystalline silicon layer is disposed between the N-type single crystal silicon layer and the N-type micro-crystalline silicon layer. In comparison with the amorphous silicon layer and the micro-crystalline silicon layer, the N-type single crystal silicon layer can generate much more photo current. The addition of the amorphous silicon layer outside of the N-type single crystal silicon layer can increase the open circuit current, the addition of the micro-crystalline silicon layer can reduce the band offset possibly occurred between the amorphous and single crystal silicon layers so that the conversion efficiency of the device can be enhanced by compensating the weakness of the single N-type crystal silicon. Furthermore, the micro-crystalline silicon layer has the better ability to resist light-induced degradation than the amorphous silicon layer, so as to enhance the device performance.

Description

Solar cell component

The present invention relates to a solar cell element.

In recent years, due to the lack of market materials such as single crystal germanium and polycrystalline germanium, the price has soared, making the production capacity of many twin solar cell manufacturers unable to rise, while the thin film solar cell (Silicon Thin-Film Solar Cell) uses a glass substrate and is rhodium-plated. The membrane uses decane (SiH ₄ ) and hydrogen (H ₂ ), and the overall element film thickness is only a few micrometers, so there is no problem of lack of material. In addition, the temperature coefficient of the thin film solar cell is low, the component open circuit voltage is lowered slowly when the temperature rises, and the component efficiency loss is less than that of the twinned solar cell. On the other hand, in the case of low illumination with an illuminance of less than 10 W/m ² , the tantalum thin film solar cell can still maintain 90% of the AM 1.5 illumination, whereas the conventional twin solar cell can only maintain 20% in this case.

Compared with the general market share of more than 80% of crystalline solar cells, tantalum thin film solar cells have the advantages of low price and low temperature effect. It is estimated that the total power generation of tantalum thin film solar cells is different in terms of power generation throughout the year. The location will be higher than that of the twin crystal solar cells by about 5 to 25%, which is the main focus of the development of solar cells at this stage.

However, since the main body of the thin-film solar cell is an amorphous layer (A-Si), the advantage is that the open circuit voltage is high, but the defect is that the short-circuit current is low, and the conductivity of the film is lowered under the irradiation of sunlight. This causes the component to produce a light decay phenomenon. On the other hand, a single crystal germanium solar cell has a high short-circuit current, but its open circuit voltage is small. If an amorphous germanium layer is plated on both sides of a single crystal germanium to form an HIT structure, the open circuit voltage is increased, but The contact of the wafer with the single crystal germanium creates an energy barrier, thereby increasing the composite probability of the electron hole and the power generation efficiency is limited.

Therefore, how to provide a solar cell element, which can effectively increase the open circuit voltage and the short circuit current and reduce the electron and hole combination probability and improve the photoelectric conversion efficiency, has become one of the important topics.

In view of the above problems, an object of the present invention is to provide a solar cell element capable of effectively increasing an open circuit voltage and a short-circuit current and reducing the electron and hole combination probability to improve photoelectric conversion efficiency.

To achieve the above object, the present invention provides a solar cell element comprising a P-type amorphous germanium layer, an N-type microcrystalline germanium layer, an N-type single crystal germanium layer, an intrinsic amorphous germanium layer, and an intrinsic crystallite.矽 layer. The N-type single crystal germanium layer is disposed between the P-type amorphous germanium layer and the N-type microcrystalline germanium layer. The intrinsic amorphous germanium layer is disposed between the N-type single crystal germanium layer and the P-type amorphous germanium layer. The intrinsic microcrystalline germanium layer is disposed between the N-type single crystal germanium layer and the N-type microcrystalline germanium layer.

In order to achieve the above object, the present invention further provides a solar cell element comprising an N-type amorphous germanium layer, a P-type microcrystalline germanium layer, an N-type single crystal germanium layer, an intrinsic amorphous germanium layer, and an essential micro Crystalline layer. The N-type single crystal germanium layer is disposed between the N-type amorphous germanium layer and the P-type microcrystalline germanium layer. The intrinsic amorphous germanium layer is disposed between the N-type single crystal germanium layer and the N-type amorphous germanium layer. The intrinsic microcrystalline germanium layer is disposed between the N-type single crystal germanium layer and the P-type microcrystalline germanium layer.

As described above, the solar cell designed by the present invention in an innovative concept includes an amorphous germanium layer, a single crystal germanium layer, and a microcrystalline germanium layer. Compared with the non-twisted layer and the microcrystalline layer, the N-type single crystal germanium layer can generate a large photocurrent, and the addition of an amorphous germanium layer on the outside can increase the open circuit voltage, and the use of the microcrystalline germanium can reduce the amorphous The energy barrier between the crucible and the single crystal crucible reduces the composite probability of the electron hole and improves the battery conversion efficiency. In addition, the microcrystalline germanium layer has better light recession resistance than the amorphous germanium layer, and improves the device performance. In addition, the single crystal germanium layer can greatly enhance the photoelectric conversion efficiency of the solar cell.

In addition, in the present invention, the solar cell further includes an intrinsic amorphous germanium layer, which can serve as a barrier layer for electron hole recombination, thereby improving photoelectric conversion efficiency.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a solar cell element according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings, wherein the same elements will be described with the same reference numerals.

Please refer to FIG. 1. FIG. 1 is a schematic diagram of a solar cell element 1 according to a preferred embodiment of the present invention. In the present embodiment, the solar cell element 1 comprises a P-type amorphous germanium layer (P-type a-Si:H) 11, an N-type microcrystalline germanium layer (N-type μc-Si:H) 12, a N-type c-Si layer, an intrinsic amorphous layer (i-layer a-Si:H) 14 and an intrinsic microcrystalline layer (i-layer μc-Si:H) 15. The N-type single crystal germanium layer 13 is provided between the P-type amorphous germanium layer 11 and the N-type microcrystalline germanium layer 12. The intrinsic amorphous germanium layer 14 is disposed between the N-type single crystal germanium layer 13 and the P-type amorphous germanium layer 11. The intrinsic microcrystalline germanium layer 15 is disposed between the N-type single crystal germanium layer 13 and the N-type microcrystalline germanium layer 12. The N-type single crystal germanium layer 13 is a single crystal substrate.

The P-type amorphous germanium layer 11 can be formed, for example, by a Radio Frequency Plasma Enhancement Chemical Vapor Deposition (RF-PECVD), and is provided with decane (SiH ₄ ) and hydrogen (H ₂ ). As a doping gas B ₂ H ₆ , a P-type hydrogenated amorphous amorphous silicon (a-Si:H) film is deposited. For example, the substrate temperature is set to about 150 to 300 ° C, the chamber pressure is 0.1 to 1 torr, the deposition rate is about 0.1 to 0.3 nm/s, the film thickness is about 10 nm, and the energy level is about 1.7 to 1.8 eV. If the methane is introduced, the energy level of the P-type amorphous germanium layer 11 can reach 2 eV.

The N-type microcrystalline germanium layer 12 can be formed, for example, by a high-density plasma coating method (VHF-PECVD, which produces a plasma frequency of 26 to 133 MHz), and is supplied with SiH ₄ and H ₂ and PH ₃ as a doping gas. A N-type hydrogenated micro-crystalline silicon (μ-Si:H) film was deposited. For example, the substrate temperature is set to be about 150 to 300 ° C, the chamber pressure is 0.1 to 1 torr, the deposition rate is about 0.1 nm/s, the film thickness is about 20 to 40 nm, and the energy level is about 1.1 eV.

The intrinsic amorphous germanium layer 14 can be formed, for example, by a radio frequency plasma-assisted chemical vapor deposition method, and a hydrogenated intrinsic silicon film is deposited by passing silane (SiH ₄ ) and hydrogen (H ₂ ). For example, the substrate temperature is set to about 150 to 300 ° C, the chamber pressure is 0.1 to 1 torr, the deposition rate is about 0.1 to 0.3 nm/s, the film thickness is about 10 nm, and the energy level is about 1.7 to 1.8 eV.

The intrinsic microcrystalline germanium layer 15 can be formed, for example, by a high-density plasma coating method (VHF-PECVD, which produces a plasma frequency of 26 to 133 MHz), and is passed through SiH ₄ and H ₂ at a deposition rate of about 0.1 to 0.3 nm/ s, the film thickness is about 10 nm, and the energy level is about 1.1 eV.

In addition, the solar cell element 1 may further include two transparent electrode layers 16, 17 disposed such that the P-type amorphous germanium layer 11 is located between the transparent electrode layer 16 and the intrinsic amorphous germanium layer 14, and the N-type microcrystalline germanium Layer 12 is between transparent electrode layer 17 and intrinsic microcrystalline layer 15. The transparent electrode layers 16 and 17 may be, for example, a transparent conductive oxide film material (Transparent Conducting Oxide) deposited as a sputtering electrode, and the transparent conductive oxide film material may be, for example, indium tin oxide (ITO) or zinc oxide (ZnO). This is illustrative and not limiting. In the present embodiment, the transparent electrode layers 16, 17 have a film thickness of about 80 to 100 nm, a transmittance of 85% or more, and a specific resistance of about 0.01 to 0.03 Ω-cm.

In addition, the solar cell element 1 further includes two metal electrode layers 18, 19 disposed such that the transparent electrode layer 16 is located between the metal electrode layer 18 and the P-type amorphous germanium layer 11, and the transparent electrode layer 17 is located at the metal electrode layer. 19 is between the N-type microcrystalline germanium layer 12. The material of the metal electrode layers 18, 19 may be, for example, aluminum, silver, copper or other electrically conductive metal. Here, the embodiment is exemplified by aluminum. The metal electrode layers 18, 19 have a thickness of about 150 to 200 nm. The metal electrode layers 18, 19 have a pattern.

Please refer to FIG. 2. FIG. 2 is a schematic diagram of another solar cell element 2 according to a preferred embodiment of the present invention. In the present embodiment, the solar cell element 2 comprises an N-type amorphous germanium layer (N-type a-Si:H) 21 and a P-type microcrystalline germanium layer (P-type μc-Si:H) 22, one. N-type c-Si layer, an intrinsic amorphous layer (i-layer a-Si:H) 24, and an intrinsic microcrystalline layer (i-layer μc-Si:H) 25. The N-type single crystal germanium layer 23 is provided between the N-type amorphous germanium layer 21 and the P-type microcrystalline germanium layer 22. The intrinsic amorphous germanium layer 24 is disposed between the N-type single crystal germanium layer 23 and the N-type amorphous germanium layer 21. The intrinsic microcrystalline germanium layer 25 is disposed between the P-type single crystal germanium layer 23 and the p-type microcrystalline germanium layer 22. The P-type single crystal germanium layer is a single crystal substrate.

In the present embodiment, the main difference from the foregoing embodiment is that the P-type amorphous germanium layer 11 is changed to the N-type amorphous germanium layer 21, the N-type microcrystalline germanium layer 12 is changed to the P-type microcrystalline germanium layer 22, and the like. For example, the intrinsic amorphous germanium layer 24, the intrinsic microcrystalline germanium layer 25, the transparent electrode layers 26, 27, and the metal electrode layers 28, 29 are the same as the previous embodiments, and all processes are the same as those of the previous embodiment, as described above. This will not be repeated here.

The N-type amorphous germanium layer 21 can be formed, for example, by a Radio Frequency Plasma Enhancement Chemical Vapor Deposition (RF-PECVD), and is provided with decane (SiH ₄ ) and hydrogen (H _{2 ).} And as a pH _{3 of a} doping gas, an N-type hydrogenated amorphous amorphous silicon (a-Si:H) film is deposited. For example, the substrate temperature is set to about 150 to 300 ° C, the chamber pressure is 0.1 to 1 torr, the deposition rate is about 0.1 to 0.3 nm/s, the film thickness is about 10 nm, and the energy level is about 1.7 to 1.8 eV.

The P-type microcrystalline germanium layer 22 can be formed, for example, by a high-density plasma coating method (VHF-PECVD, which produces a plasma frequency of 26 to 133 MHz), and is supplied with SiH ₄ and H ₂ and B ₂ H as a doping gas. _6. Depositing a P-type hydrogenated micro-crystalline silicon (μ-Si:H) film. For example, the substrate temperature is set to be about 150 to 300 ° C, the chamber pressure is 0.1 to 1 torr, the deposition rate is about 0.1 nm/s, the film thickness is about 20 to 40 nm, and the energy level is about 1.1 eV.

In addition, the amorphous germanium layer or the microcrystalline germanium layer may be doped with at least one of the group IIIA to VA of the element table. For example, the amorphous germanium layer can be formed as an amorphous germanium telluride (a-SiGe:H) layer in which the germanium content can be adjusted to change the energy level of the amorphous germanium telluride (a-SiGe:H) layer. It has better energy level matching with the buried microcrystalline germanium layer to further increase the photoelectric conversion efficiency.

In summary, the solar cell designed by the present invention in an innovative concept includes an amorphous germanium layer, a single crystal germanium layer, and a microcrystalline germanium layer. Compared with the non-twisted layer and the microcrystalline layer, the N-type single crystal germanium layer can generate a large photocurrent, and the addition of an amorphous germanium layer on the outside can increase the open circuit voltage, and the use of the microcrystalline germanium can reduce the amorphous The energy barrier between the crucible and the single crystal crucible reduces the composite probability of the electron hole and improves the battery conversion efficiency. In addition, the microcrystalline germanium layer has better light recession resistance than the amorphous germanium layer, and improves the device performance. In addition, the single crystal germanium layer can greatly enhance the photoelectric conversion efficiency of the solar cell.

In addition, in the present invention, the solar cell further includes an intrinsic amorphous germanium layer, which can serve as a barrier layer for electron hole recombination, thereby improving photoelectric conversion efficiency.

The above is intended to be illustrative only and not limiting. Any equivalent modifications or alterations to the spirit and scope of the invention are intended to be included in the scope of the appended claims.

1, 2. . . Solar cell component

11. . . P-type amorphous germanium layer

12. . . N-type microcrystalline layer

13,23. . . N-type single crystal layer

14, 24. . . Intrinsic amorphous layer

15,25. . . Intrinsic microcrystalline layer

16, 17, 26, 27. . . Transparent electrode layer

18, 19, 28, 29. . . Metal electrode layer

twenty one. . . N-type amorphous germanium layer

twenty two. . . P-type microcrystalline layer

1 is a schematic view of a solar cell component in accordance with a preferred embodiment of the present invention;

2 is a schematic view of another solar cell element in accordance with a preferred embodiment of the present invention.

1. . . Solar cell component

11. . . P-type amorphous germanium layer

12. . . N-type microcrystalline layer

13. . . N-type single crystal layer

14. . . Intrinsic amorphous layer

15. . . Intrinsic microcrystalline layer

16, 17. . . Transparent electrode layer

18, 19. . . Metal electrode layer

Claims (10)

A solar cell component comprising: a P-type amorphous germanium layer; an N-type microcrystalline germanium layer; and an N-type single crystal germanium layer disposed between the P-type amorphous germanium layer and the N-type microcrystalline germanium layer An intrinsic amorphous germanium layer disposed between the N-type single crystal germanium layer and the P-type amorphous germanium layer; and an intrinsic microcrystalline germanium layer disposed on the N-type single crystal germanium layer and the N-type micro Between the layers of the wafer. The solar cell component of claim 1, further comprising: a transparent electrode layer disposed such that the P-type amorphous germanium layer is between the transparent electrode layer and the intrinsic amorphous germanium layer. The solar cell component of claim 2, further comprising: a metal electrode layer disposed such that the transparent electrode layer is between the metal electrode layer and the P-type amorphous germanium layer. The solar cell component of claim 1, further comprising: a transparent electrode layer disposed such that the N-type microcrystalline germanium layer is between the transparent electrode layer and the essential microcrystalline germanium layer. The solar cell component of claim 4, further comprising: a metal electrode layer disposed such that the transparent electrode layer is between the metal electrode layer and the N-type microcrystalline layer. A solar cell component comprising: an N-type amorphous germanium layer; a P-type microcrystalline germanium layer; and an N-type single crystal germanium layer disposed between the N-type amorphous germanium layer and the P-type microcrystalline germanium layer An intrinsic amorphous germanium layer disposed between the N-type single crystal germanium layer and the N-type amorphous germanium layer; and an intrinsic microcrystalline germanium layer disposed on the N-type single crystal germanium layer and the P-type micro Between the layers of the wafer. The solar cell component of claim 6, further comprising: a transparent electrode layer disposed such that the P-type microcrystalline germanium layer is between the transparent electrode layer and the essential microcrystalline germanium layer. The solar cell component of claim 7, further comprising: a metal electrode layer disposed such that the transparent electrode layer is located between the metal electrode layer and the P-type microcrystalline layer. The solar cell component of claim 6, further comprising: a transparent electrode layer disposed such that the N-type amorphous germanium layer is between the transparent electrode layer and the intrinsic amorphous germanium layer. The solar cell component of claim 9, further comprising: a metal electrode layer disposed such that the transparent electrode layer is between the metal electrode layer and the N-type amorphous germanium layer.