Improved metastability and performance of amorphous silicon solar cells

2014 ◽  
Vol 1666 ◽  
Author(s):  
Takuya Matsui ◽  
Adrien Bidiville ◽  
Hitoshi Sai ◽  
Takashi Suezaki ◽  
Mitsuhiro Matsumoto ◽  
...  

ABSTRACTWe show that high-efficiency and low-degradation hydrogenated amorphous silicon (a-Si:H) p-i-n solar cells can be obtained by depositing absorber layers in a triode-type plasma-enhanced chemical vapor deposition (PECVD) process. Although the deposition rate is relatively low (0.01-0.03 nm/s) compared to the conventional diode-type PECVD process (∼0.2 nm/s), the light-induced degradation in conversion efficiency of single-junction solar cell is substantially reduced (Δη/ηini∼10%) due to the suppression of light-induced metastable defects in the a-Si:H absorber layer. So far, we have attained an independently-confirmed stabilized efficiency of 10.11% for a 220-nm-thick a-Si:H solar cell which was light soaked under 1 sun illumination for 1000 hours at cell temperature of 50°C. We further demonstrate that stabilized efficiencies as high as 10% can be maintained even when the solar cell is thickened to >300 nm.

1999 ◽  
Vol 557 ◽  
Author(s):  
X. B. Liao ◽  
J. Walker ◽  
X. Deng

AbstractIn high efficiency narrow bandgap (NBG) a-SiGe solar cells, thin buffer layers of unalloyed hydrogenated amorphous silicon (a-Si) are usually used at the interfaces between the a-SiGe intrinsic layer and the doped layers. We investigated the effect of inserting additional a-SiGe interface layers between these a-Si buffer layers and the a-SiGe absorber layer. We found that such additional interface layers increase solar cell VOC and FF sizably, most likely due to the reduction or elimination of the abrupt bandgap discontinuity between the a-SiGe absorber layer and the a-Si buffer layers. With these improved narrow bandgap solar cells incorporated into the fabrication of triple-junction a-Si based solar cells, we obtained triple cells with initial efficiency of 10.6%.


2021 ◽  
Author(s):  
Yingying zhang ◽  
Mohammad Ali Eslamisaray ◽  
Tianli Feng ◽  
Uwe Kortshagen ◽  
Xiaojia Wang

Hydrogenated amorphous silicon (a-Si:H) has been of keen interest as a thin-film semiconductor and superb passivation layer in high-efficiency silicon solar cells due to its low cost, low processing temperature,...


2001 ◽  
Vol 664 ◽  
Author(s):  
Richard S. Crandall ◽  
Jeffrey Yang ◽  
Subhendu Guha

ABSTRACTThe fundamental ingredient lacking in solar cell modeling is the spatial distribution of defects. To gain this information, we use drive-level capacitance profiling (DLCP) on hydrogenated amorphous silicon solar cells. We find the following: Near the p-i interface the defect density is high, decreasing rapidly into the interior, reaching low values in the central region of the cell, and rising rapidly again at the n-i interface. The states in the central region are neutral dangling-bond defects whose density agrees with those typically found in similar films. However, those near the interfaces with the doped layers are charged dangling bonds in agreement with the predictions of defect thermodynamics. We correlate the changes in solar cell efficiency owing to intense illumination with changes in the defect density throughout the cell. Defects in the central region of the cell increase to values typically found in companion films. We describe the measurements and interpretation of DLCP for solar cells with the aid of a solar cell simulation.


2006 ◽  
Vol 910 ◽  
Author(s):  
Qi Wang ◽  
Matt P. Page ◽  
Eugene Iwancizko ◽  
Yueqin Xu ◽  
Yanfa Yan ◽  
...  

AbstractWe have achieved an independently-confirmed 17.8% conversion efficiency in a 1-cm2, p-type, float-zone silicon (FZ-Si) based heterojunction solar cell. Both the front emitter and back contact are hydrogenated amorphous silicon (a-Si:H) deposited by hot-wire chemical vapor deposition (HWCVD). This is the highest reported efficiency for a HWCVD silicon heterojunction (SHJ) solar cell. Two main improvements lead to our most recent increases in efficiency: 1) the use of textured Si wafers, and 2) the application of a-Si:H heterojunctions on both sides of the cell. Despite the use of textured c-Si to increase the short-circuit current, we were able to maintain the same 0.65 V open-circuit voltage as on flat c-Si. This is achieved by coating a-Si:H conformally on the c-Si surfaces, including covering the tips of the anisotropically-etched pyramids. A brief atomic H treatment before emitter deposition is not necessary on the textured wafers, though it was helpful in the flat wafers. It is essential to high efficiency SHJ solar cells that the emitter grows abruptly as amorphous silicon, instead of as microcrystalline or epitaxial Si. The contact on each side of the cell comprises a thin (< 5 nm) low substrate temperature (~100°C) intrinsic a-Si:H layer, followed by a doped layer. Our intrinsic layers are deposited at 0.3-1.2 nm/s. The doped emitter and back-contact layers were deposited at a higher temperature (>200°C) and grown from PH3/SiH4/H2 and B2H6/SiH4/H2 doping gas mixtures, respectively. This combination of low (intrinsic) and high (doped layer) growth temperatures was optimized by lifetime and surface recombination velocity measurements. Our rapid efficiency advance suggests that HWCVD may have advantages over plasma-enhanced (PE) CVD in fabrication of high-efficiency heterojunction c-Si cells; there is no need for process optimization to avoid plasma damage to the delicate, high-quality, Si wafers.


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
F. X. Abomo Abega ◽  
A. Teyou Ngoupo ◽  
J. M. B. Ndjaka

Numerical modelling is used to confirm experimental and theoretical work. The aim of this work is to present how to simulate ultrathin hydrogenated amorphous silicon- (a-Si:H-) based solar cells with a ITO BRL in their architectures. The results obtained in this study come from SCAPS-1D software. In the first step, the comparison between the J-V characteristics of simulation and experiment of the ultrathin a-Si:H-based solar cell is in agreement. Secondly, to explore the impact of certain properties of the solar cell, investigations focus on the study of the influence of the intrinsic layer and the buffer layer/absorber interface on the electrical parameters ( J SC , V OC , FF, and η ). The increase of the intrinsic layer thickness improves performance, while the bulk defect density of the intrinsic layer and the surface defect density of the buffer layer/ i -(a-Si:H) interface, respectively, in the ranges [109 cm-3, 1015 cm-3] and [1010 cm-2, 5 × 10 13  cm-2], do not affect the performance of the ultrathin a-Si:H-based solar cell. Analysis also shows that with approximately 1 μm thickness of the intrinsic layer, the optimum conversion efficiency is 12.71% ( J SC = 18.95   mA · c m − 2 , V OC = 0.973   V , and FF = 68.95 % ). This work presents a contribution to improving the performance of a-Si-based solar cells.


1991 ◽  
Vol 30 (Part 1, No. 8) ◽  
pp. 1635-1640 ◽  
Author(s):  
Katsuhiko Higuchi ◽  
Katsuya Tabuchi ◽  
Koeng Su Lim ◽  
Makoto Konagai ◽  
Kiyoshi Takahashi

Sign in / Sign up

Export Citation Format

Share Document