scholarly journals Study on the deposition of amorphous silicon and ito thin films for heterojunction solar cell application

2013 ◽  
Vol 16 (1) ◽  
pp. 101-111
Author(s):  
Chien Mau Dang ◽  
Tung Thanh Bui ◽  
Hung Thanh Le ◽  
Vu Ngoc Hoang ◽  
Linh Ngoc Tran ◽  
...  
Keyword(s):  
Solar Cell ◽  
Amorphous Silicon ◽  
Sheet Resistance ◽  
Indium Tin Oxide ◽  
High Efficiency ◽  
Cell Structure ◽  
Chemical Vapor ◽  
Solar Cell Application ◽  
Ito Thin Films ◽  
P Type

In the heterojunction with intrinsic thin-layer (HIT) solar cell structure studied in this work, an intrinsic amorphous silicon (a-Si) layer followed by a n-type amorphous silicon was deposited on a p-type Czochralski (CZ) monocrystalline silicon (c-Si) wafer by plasma enhanced chemical vapor deposition (PECVD) method to form an heterojunction device. Then, indium tin oxide (ITO) layer was formed by DC magnetron sputtering as the top electrode and the anti-reflection coating layer. In order to obtain the high efficiency heterojunction structure, two important aspects were focused: improving the passivation properties of a-Si/c-Si heterojunction and reducing the light absorption and the sheet resistance of ITO layers. It was found that hydrogenated amorphous silicon (a- Si:H) layers can be grown at low substrate temperature, about 200°C. High-quality ITO layers with the sheet resistance less than 15 ohm/sq and the transmittance of about 70%, can be deposited at relatively low DC power (50W).

17.8%-efficient Amorphous Silicon Heterojunction Solar Cells on p-type Silicon Wafers

2006 ◽  
Vol 910 ◽  
Author(s):  
Qi Wang ◽  
Matt P. Page ◽  
Eugene Iwancizko ◽  
Yueqin Xu ◽  
Yanfa Yan ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Amorphous Silicon ◽  
High Efficiency ◽  
Short Circuit ◽  
Open Circuit ◽  
Layer Growth ◽  
Surface Recombination Velocity ◽  
Back Contact ◽  
P Type

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.

Structural and Optical Properties of a-Si:H/μc-Si:H:B Junctions in the a-Si:H-Based n-i-P Solar Cell Configuration

1997 ◽  
Vol 467 ◽  
Author(s):  
Joohyun Kohi ◽  
H. Fujiwara ◽  
C. R. Wronski ◽  
R. W. Collins
Keyword(s):  
Optical Properties ◽  
Solar Cell ◽  
Single Phase ◽  
Cell Structure ◽  
Chemical Vapor ◽  
Average Crystallite Size ◽  
Microcrystalline Silicon ◽  
Solar Cell Structure ◽  
P Type ◽  
Hydrogenated Amorphous

ABSTRACTWe have extended previous real time spectroscopie ellipsometry (RTSE) capabilities in order to investigate the effects of H2-plasma treatment of i-type hydrogenated amorphous silicon (a-Si:H) on the deposition of the overlying p-type microcrystalline silicon (μc-Si:H:B)) in the formation of an n-i-p solar cell structure. In this study, we compare in detail the nucleation and growth of p-layers by plasma-enhanced chemical vapor deposition (PECVD) from SiH4 highly diluted in H2 on the surfaces of untreated and H2-plasma treated a-Si:H i-layers. We find that for intended single-phase μc-Si:H:B p-layer PECVD under optimum conditions on an untreated i-layer surface, a wide gap (∼2.0 eV Taue gap) amorphous layer nucleates and grows in the first ∼150 Å. This layer develops uniformly to a bulk thickness of ∼150 Å, but gradually acquires a crystalline structure for thicknesses greater than the desired p-layer thickness (200 Å). In contrast, for p-layer PECVD under identical conditions on the H2-plasma treated i-layer, high-density crystalline nuclei form immediately. This conclusion is drawn on the basis of the unique optical properties of the bulk p-layer that develops on the surface of the H2-plasma treated i-layer. Specifically, an absorption onset near ∼2.5 eV is observed for a 48 Å fully-coalesced p-layer, as measured by RTSE at 200°C. For this μc-Si:H:B p-layer, the optical gap decreases by ∼0.15 eV with increasing thickness from 50 to 200 Å. This effect is attributed to a reduction in the quantum confinement energy with an increase in the average crystallite size in the film.

Improved metastability and performance of amorphous silicon solar cells

2014 ◽  
Vol 1666 ◽  
Author(s):  
Takuya Matsui ◽  
Adrien Bidiville ◽  
Hitoshi Sai ◽  
Takashi Suezaki ◽  
Mitsuhiro Matsumoto ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Amorphous Silicon ◽  
High Efficiency ◽  
Chemical Vapor ◽  
Silicon Solar Cells ◽  
Cell Temperature ◽  
Single Junction Solar Cell ◽  
And Performance ◽  
Hydrogenated Amorphous

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.

Passivation of Plasma Oxidized SiOX Layer Using Field Effect on p-type Emitter Surface for High Efficiency c-Si Solar Cell Application

2017 ◽  
Vol 13 (4) ◽  
pp. 49-54
Author(s):  
Sooyoung Park ◽  
Gyungbae Shim ◽  
Sanguk Han ◽  
Shihyun Ahn ◽  
Cheolmin Park ◽  
...  
Keyword(s):  
Solar Cell ◽  
Field Effect ◽  
High Efficiency ◽  
Emitter Surface ◽  
Solar Cell Application ◽  
Si Solar Cell ◽  
P Type

scholarly journals Analysis increase in the efficiency of a-Si: H solar cell due to the addition of an intrinsic layer to the p-i-n structure by ellipsometric spectroscopy

2021 ◽  
Author(s):  
SONI PRAYOGI ◽  
Yoyok Cahyono ◽  
Darminto D
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Indium Tin Oxide ◽  
Cell Structure ◽  
Chemical Vapor ◽  
Sharp Decrease ◽  
Infrared Region ◽  
Light Region ◽  
Solar Cell Structure ◽  
Good Transparency

Abstract Backround: In this study, we report for the first time that the addition of an intrinsic layer to the a-Si: H p-i-n solar cell structure greatly enhances the conversion efficiency. The a-Si: H p-i-n solar cells were grown using Plasma Enhanced Chemical Vapor Deposition (PECVD) techniques on the Indium Tin Oxide (ITO) substrate and added an intrinsic layer with the p-i1-i2-n structure in order to prevent sunlight energy from being absorbed the first intrinsic layer can be absorbed by the second intrinsic layer. Result The a-Si: H p-i-n and p-i1-i2-n solar cells were characterized including optical properties, electrical properties, surface morphology, thickness, band-gap using Ellipsometric Spectroscopy (ES). Furthermore, from the optical constant and thin film thickness, the reflectance and transmittance of each sample were obtained. The p-i-n and p-i1-i2-n samples show good transparency in the infrared region and this transparency decreases in the visible light region shows an interference pattern with a sharp decrease in transmission at the absorption edge and the performance of solar cells (curve I-V) measured by use sun simulator and sunshine. Conclussion: Our results show that there is a very good increase in the efficiency of the a-Si: H p-i1-i2-n solar cells by 58.6% of the original p-i-n structure.

Light Trapping Potential of Hexagonal Array Silicon Nanohole Structure for Solar Cell Application

2012 ◽  
Vol 512-515 ◽  
pp. 90-96 ◽  
Author(s):  
Nor Afifah Yahaya ◽  
Noboru Yamada ◽  
Tadachika Nakayama
Keyword(s):  
Solar Cell ◽  
Electric Field ◽  
Indium Tin Oxide ◽  
High Efficiency ◽  
Field Enhancement ◽  
Hexagonal Array ◽  
Multiple Reflections ◽  
Solar Cell Application ◽  
Entire Spectrum ◽  
Spectrum Range

The reflectance of the hexagonal array silicon nanohole structure was systematically studied using various measurements and through simulations. It was found that the hexagonal array silicon nanohole can reduce the reflectance along the entire spectrum range by approximately 6%. It is suggested that the enhancement of the electric field intensity at short wavelength is mainly due to the large surface area provided by the nanohole structure, while multiple reflections occurring in the nanohole contribute to electric field enhancement in the long wavelength range. In addition, the simulation of a hexagonal array silicon nanohole coated with a thin layer of indium tin oxide (ITO) was carried out. The results show that reflectance is greatly decreased along nearly the entire spectrum range, except from 400 nm to 440 nm, and almost zero reflectance is achieved at wavelengths from 650 nm to 750 nm. The results provide a practical guideline to the design and fabrication of a low-reflectance, and as a consequence, a high-efficiency hexagonal array silicon nanohole solar cell.

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