Options
Silicon thin films prepared by remote low frequency inductively coupled plasma for solar cell applications
Loading...
Type
Thesis
Author
Guo, Yingnan
Supervisor
Xu, Shuyan
Abstract
In this thesis, hydrogenated amorphous silicon (a-Si:H) and microcrystalline silicon (μcSi:H) thin films were studied by remote low frequency inductively coupled plasma chemical vapour deposition (ICP-CVD) system and the applications of both a-Si:H and μc-Si:H thin films in photovoltaics (PV) were investigated.
First, the phase evolution of ICP-CVD was investigated. Silicon thin films were deposited by ICP-CVD at different setting between substrate and antenna. The influence of radio-frequency (RF) power, distance, and hydrogen and silane flow rate on crystallinity of silicon thin films was investigated.
Then a-Si:H thin films prepared by semi-remote ICP-CVD were applied on crystalline silicon wafers for surface passivation. The effects of precursor gas flow rate, RF power and post-deposition processing conditions on the passivation quality were investigated and relationships between the passivation effect and thin film properties were established. A minority carrier lifetime of 1.17×10-3 seconds was obtained for sample passivated by 50 nm amorphous silicon thin film.
The influence of hydrogen plasma treatment on the passivation properties of ultra thin a-Si:H films prepared by semi-remote ICP-CVD was studied. The treatment process was implemented by both PECVD and semi-remote ICP-CVD. The influence of processing temperature, RF power and duration were studied. The differences between these two technologies were also compared. Silicon wafer passivated by a-Si:H films with 10 nm thickness can achieve a minority carrier lifetime of 3.35×10-4 seconds after hydrogen plasma treatment by PECVD.
Amorphous thin films deposited via remote ICP-CVD were applied as surface passivation and the passivation quality and the properties of a-Si:H films were studied. The influence of post-deposition annealing temperature, deposition temperature and flow rate of precursor gas on passivation effect and film properties were investigated. A minority carrier lifetime of 2.32×10-3 seconds can be achieved through the passivation of a-Si:H films with 10 nm thickness. After adding an additional heavily doped n-type a-Si:H films over the passivation layer by PECVD, the minority carrier lifetime was 2.54×10-3 seconds.
Finally, we deposite μc-Si:H films by remote ICP-CVD, and investigated the influence RF power and SiH4 flow rate on the microstructure and electrical properties of thin films. Device quality film was obtained. We then applied μc-Si:H thin films as the activation layer to fabricate a glass/AZO/p-i-n/AZO/Al microcrystalline thin film solar cell in remote ICP-CVD and studied the performances of thin film solar cell with absorption layers deposited by different condition. The μc-Si:H thin film solar cell has a opencircuit voltage of about 655mV, short-circuit current density of about 15.3 mA/cm2 , a fill factor of about 40.5%, and conversion efficiency was 4.05%.
First, the phase evolution of ICP-CVD was investigated. Silicon thin films were deposited by ICP-CVD at different setting between substrate and antenna. The influence of radio-frequency (RF) power, distance, and hydrogen and silane flow rate on crystallinity of silicon thin films was investigated.
Then a-Si:H thin films prepared by semi-remote ICP-CVD were applied on crystalline silicon wafers for surface passivation. The effects of precursor gas flow rate, RF power and post-deposition processing conditions on the passivation quality were investigated and relationships between the passivation effect and thin film properties were established. A minority carrier lifetime of 1.17×10-3 seconds was obtained for sample passivated by 50 nm amorphous silicon thin film.
The influence of hydrogen plasma treatment on the passivation properties of ultra thin a-Si:H films prepared by semi-remote ICP-CVD was studied. The treatment process was implemented by both PECVD and semi-remote ICP-CVD. The influence of processing temperature, RF power and duration were studied. The differences between these two technologies were also compared. Silicon wafer passivated by a-Si:H films with 10 nm thickness can achieve a minority carrier lifetime of 3.35×10-4 seconds after hydrogen plasma treatment by PECVD.
Amorphous thin films deposited via remote ICP-CVD were applied as surface passivation and the passivation quality and the properties of a-Si:H films were studied. The influence of post-deposition annealing temperature, deposition temperature and flow rate of precursor gas on passivation effect and film properties were investigated. A minority carrier lifetime of 2.32×10-3 seconds can be achieved through the passivation of a-Si:H films with 10 nm thickness. After adding an additional heavily doped n-type a-Si:H films over the passivation layer by PECVD, the minority carrier lifetime was 2.54×10-3 seconds.
Finally, we deposite μc-Si:H films by remote ICP-CVD, and investigated the influence RF power and SiH4 flow rate on the microstructure and electrical properties of thin films. Device quality film was obtained. We then applied μc-Si:H thin films as the activation layer to fabricate a glass/AZO/p-i-n/AZO/Al microcrystalline thin film solar cell in remote ICP-CVD and studied the performances of thin film solar cell with absorption layers deposited by different condition. The μc-Si:H thin film solar cell has a opencircuit voltage of about 655mV, short-circuit current density of about 15.3 mA/cm2 , a fill factor of about 40.5%, and conversion efficiency was 4.05%.
Date Issued
2016
Call Number
TK7871.15.S56 Guo
Date Submitted
2016