کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5347122 | 1503558 | 2017 | 6 صفحه PDF | دانلود رایگان |
- ZnO:Ga film with perpetual c-axis orientation at low TS by RF magnetron sputtering.
- High conductivity (200Â SÂ cmâ1) and elevated transmission (â¼93% at 500Â nm) in nano-sheet like structure.
- Si solar cell on ZnO:Ga with efficiency comparable to similar cell on U-type SnO2 coated Asahi glass.
- Higher open circuit voltage and better fill factor with ZnO:Ga than SnO2.
Technologically appropriate device friendly ZnO:Ga films have been prepared at a low growth temperature (100 °C) by changing the RF power (P) applied to the magnetron plasma. Structurally preferred c-axis orientation of the ZnO:Ga network has been attained with Iã002ã/Iã103ã > 5. The c-axis oriented grains of wurtzite ZnO:Ga grows geometrically and settles in tangentially, providing favorable conduction path for stacked layer devices. Nano-sheet like structures produced at the surface are interconnected and provide conducting path across the surface; however, those accommodate a lot of pores in between that help better light trapping and reduce the reflection loss. The optimized ZnO:Ga thin film prepared at RF power of 200 W has ã002ã oriented grains of average size â¼10 nm and exhibits a very high conductivity â¼200 S cmâ1 and elevated transmission (â¼93% at 500 nm) in the visible range. The optimized ZnO:Ga film has been used as the transparent conducting oxide (TCO) window layer of RF-PECVD grown silicon thin film solar cells in glass/TCO/p-i-n-Si/Al configuration. The characteristics of identically prepared p-i-n-Si solar cells are compared by replacing presently developed ZnO:Ga TCO with the best quality U-type SnO2 coated Asahi glass substrates. The ZnO:Ga coated glass substrate offers a higher open circuit voltage (VOC) and the higher fill factor (FF). The ZnO:Ga film being more stable in hydrogen plasma than its SnO2 counterpart, maintains a high transparency to the solar radiation and improves the VOC, while reduced diffusion of Zn across the p-layer creates less defects at the p-i interface in Si:H cells and thereby, increases the FF. Nearly identical conversion efficiency is preserved for both TCO substrates. Excellent c-axis orientation even at low growth temperature promises improved device performance by extended parametric optimization.
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Journal: Applied Surface Science - Volume 411, 31 July 2017, Pages 315-320