scholarly journals Study on Annealing Process of Aluminum Oxide Passivation Layer for PERC Solar Cells

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1052
Author(s):  
Yu-Chun Huang ◽  
Ricky Wenkuei Chuang
Keyword(s):  
Carrier Lifetime ◽  
Defect Density ◽  
Surface Recombination ◽  
Chemical Vapor ◽  
Minority Carrier Lifetime ◽  
Atomic Layer ◽  
Film Structure ◽  
Open Circuit ◽  
Annealing Process ◽  
Surface Recombination Velocity

In this study, Atomic Layer Deposition (ALD) equipment was used to deposit Al2O3 film on a p-type silicon wafer, trimethylaluminum (TMA) and H2O were used as precursor materials, and then the post-annealing process was conducted under atmospheric pressure. The Al2O3 films annealed at different temperatures between 200–500 °C were compared to ascertain the effect of passivation films and to confirm the changes in film structure and thickness before and after annealing through TEM images. Furthermore, the negative fixed charge and interface defect density were analyzed using the C-V measurement method. Photo-induced carrier generation was used to measure the effective minority carrier lifetime, the implied open-circuit voltage, and the effective surface recombination velocity of the film. The carrier lifetime was found to be the longest (2181.7 μs) for Al2O3/Si post-annealed at 400 °C. Finally, with the use of VHF (40.68 MHz) plasma-enhanced chemical vapor deposition (PECVD) equipment, a silicon nitride (SiNx) film was plated as an anti-reflection layer over the front side of the wafer and as a capping layer on the back to realize a passivated emitter and rear contact (PERC) solar cell with optimal efficiency up to 21.54%.

Influence of Surface Recombination on the Performance of SiNW Solar Cells and the Preparation of a Passivation Film

2013 ◽  
Vol 1512 ◽  
Author(s):  
Shinya Kato ◽  
Yuya Watanabe ◽  
Yasuyoshi Kurokawa ◽  
Akira Yamada ◽  
Yoshimi Ohta ◽  
...  
Keyword(s):  
Solar Cells ◽  
Silicon Nanowire ◽  
Surface Recombination ◽  
Device Simulation ◽  
Minority Carrier Lifetime ◽  
Atomic Layer ◽  
Open Circuit ◽  
Surface Recombination Velocity ◽  
Passivation Film ◽  
Recombination Velocity

ABSTRACTAl2O3 was deposited on silicon nanowire (SiNW) arrays by atomic layer deposition (ALD) as a passivation layer to reduce surface recombination velocity. As a result, effective minority carrier lifetime was improved from 1.82 to 26.2 μs. From this result, the relative low-surface recombination rate of 2.73 cm/s was obtained from a calculation using one-dimensional device simulation (PC1D). The performance of SiNW solar cells was also simulated by considering the surface recombination velocity on the side of SiNWs using two-dimensional device simulation. It was found that Al2O3 deposited by ALD can improve open-circuit voltage of SiNW solar cells even if the structure has a high-aspect ratio and large surface area. Therefore, improvement in the performance of SiNW solar cells can be expected.

Fabrication of silicon nanowire based solar cells using TiO2/Al2O3 stack thin films

MRS Advances ◽  
2018 ◽  
Vol 3 (25) ◽  
pp. 1419-1426 ◽  
Author(s):  
Yasuyoshi Kurokawa ◽  
Ryota Nezasa ◽  
Shinya Kato ◽  
Hisashi Miyazaki ◽  
Isao Takahashi ◽  
...  
Keyword(s):  
Solar Cells ◽  
Surface Passivation ◽  
Silicon Nanowire ◽  
Surface Recombination ◽  
Single Layer ◽  
Minority Carrier Lifetime ◽  
Atomic Layer ◽  
Open Circuit ◽  
Surface Reflectance ◽  
Surface Recombination Rate

ABSTRACTTo improve conversion efficiency of silicon nanowire (SiNW) solar cells, it is very important to reduce the surface recombination rate on the surface of SiNWs, since SiNWs have a large surface area. We tried to cover SiNWs with aluminum oxide (Al2O3) and titanium oxide (TiO2) by atomic layer deposition (ALD), since Al2O3 grown by ALD provides an excellent level of surface passivation on silicon wafers and TiO2 has a higher refractive index than Al2O3, leading to the reduction of surface reflectance. The effective minority carrier lifetime in SiNW arrays embedded in a TiO2/Al2O3 stack layer of 94 μsec was obtained, which was comparable to an Al2O3 single layer. The surface reflectance of SiNW solar cells was drastically decreased below around 5% in all of the wavelength range using the Al2O3/TiO2/Al2O3 stack layer. Heterojunction SiNW solar cells with the structure of ITO/p-type hydrogenated amorphous silicon (a-Si:H)/n-type SiNWs embedded in Al2O3 and TiO2 stack layer for passivation/n-type a-Si:H/back electrode was fabricated, and a typical rectifying property and open-circuit voltage of 356 mV were successfully obtained.

INFLUENCE OF THE ALKALI SURFACE TREATMENTS ON THE INTERFACE-STATES DENSITY AND MINORITY CARRIER LIFETIME IN Cz–SILICON WAFER

2018 ◽  
Vol 25 (07) ◽  
pp. 1950007
Author(s):  
M. MAOUDJ ◽  
D. BOUHAFS ◽  
N. BOUROUBA ◽  
A. EL AMRANI ◽  
R. BOUFNIK ◽  
...  
Keyword(s):  
Carrier Lifetime ◽  
Minority Carrier ◽  
Electrochemical Impedance ◽  
Alkali Treatment ◽  
Surface Recombination ◽  
Minority Carrier Lifetime ◽  
Interface States ◽  
Silicon Wafers ◽  
Surface Recombination Velocity ◽  
Minority Charge Carrier

The chemical etching of the surface of silicon wafers is a critical step in the manufacturing process of all semiconductor devices. In this contribution, we investigate the effect of alkaline etching on minority carrier lifetime and interface-states density ([Formula: see text] of silicon wafers intended to be used as solar cell substrates. After alkali treatment, the surface morphology was analyzed using scanning electron microscopy (SEM) and UV-visible-NIR optical spectroscopy. Besides and as electrical characterizations, the minority charge carrier lifetime ([Formula: see text] was measured by the Quasi-Steady State Photoconductance technique (QSSPC), and the Electrochemical Impedance Spectroscopy was used to evaluate [Formula: see text]. These results were correlated with the surface recombination velocity (SRV) calculated by fitting the experimental data to the theory. The results of characterization showed a lower SRV and a higher apparent lifetime ([Formula: see text] obtained with 23[Formula: see text]wt.% KOH etching as compared to those obtained with 30[Formula: see text]wt.% NaOH; viz. 825[Formula: see text]cm[Formula: see text] against 1500[Formula: see text]cm.s[Formula: see text] and 32[Formula: see text][Formula: see text]s against 23[Formula: see text][Formula: see text]s, respectively. These findings were corroborated by [Formula: see text] measurements which gave [Formula: see text][Formula: see text]ev[Formula: see text]cm[Formula: see text] for KOH treatment and [Formula: see text][Formula: see text]ev[Formula: see text]cm[Formula: see text] for NaOH treatment.

scholarly journals Minority-Carrier Lifetime and Surface Recombination Velocity in Single-Crystal CdTe

2015 ◽  
Vol 5 (1) ◽  
pp. 366-371 ◽  
Author(s):  
Darius Kuciauskas ◽  
Ana Kanevce ◽  
Pat Dippo ◽  
Shahram Seyedmohammadi ◽  
Roger Malik
Keyword(s):  
Single Crystal ◽  
Carrier Lifetime ◽  
Minority Carrier ◽  
Surface Recombination ◽  
Minority Carrier Lifetime ◽  
Surface Recombination Velocity ◽  
Recombination Velocity
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