| Summary: | 碩士 === 國立中央大學 === 光電科學研究所 === 98 === Anodic alumina oxide (AAO) has several advantages: easy fabrication, huge area, good regularity, and tunable periods. The deposition and etching nano-mask or specific Bowl-Al geometry, which are fabricated through AAO method, had been applied on solar cells and photonics-crystal waveguide extensively. In this study, we fabricate two structures: nano-mask and Al bulk with nano bowl geometry. Besides, apply the Al bulk with nano bowl geometry as the substrate of n-i-p a-Si:H thin film solar cells to enhance light trapping.
In the fabrication of Bowl-Al substrate, we use chemical polish, electrical-chemical polish, and multi-step anodization to promote planarization and regularity of pores or pre-site Al, respectively. We utilize 0.5M, 0.1M NaOH and 10wt% H3PO4 to remove Al2O3; the 10wt% H3PO4 has better isotropic etching. The fabricated periods from 41nm to 126.5nm shows linear relation d=-23.64+2.158V when the voltages varies from 30V to 70V. The mixed solution of CuSO4:HCl:DI Water=3g:20ml:20ml is applied to remove Al while fabricating Al2O3 nano-mask with floating method.
The periodic Bowl-Al substrate (fabricated through AAO method) is applied as the substrate of n-i-p hydrogenated amorphous silicon thin film solar cells. The original Fabry-Perot resonance of thin film stacks supports light trapping and it increases the light absorption of cells. Additionally, the excitation of surface plasmon polaritons (SPPs) on the periodic metal surface was predicted. However, the dispersion curve of SPPs does not present in the angle-resolved reflectance spectrum due to the fabricated Bowl-Al structure presents periodic property in small domain.
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