Optical and electrical properties of porous silicon layer formed on the textured surface by electrochemical etching

• Published in: Journal of semiconductors 2011-05, Vol.32 (5), p.149-152
• Main Author: 欧伟英 赵雷 刁宏伟 张俊 王文静
• Format: Article
• Language: English
• Subjects: Anodizing; Electrical properties; Optical properties; Porous silicon; Reflectance; Reflectivity; Semiconductors; TMAH; Wavelengths; 光学; 多孔硅; 氧化时间; 电化学腐蚀; 电学特性; 表面纹理; 阳极氧化处理
• ISSN: 1674-4926
• DOI: 10.1088/1674-4926/32/5/056002

Porous silicon （PS） layers were formed on textured crystalline silicon by electrochemical etching in HF- based electrolyte. Optical and electrical properties of the TMAH textured surfaces with PS formation are studied. Moreover, the influences of the initial structures and the anodizing time on the optical and electrical properties of the surfaces after PS formation are investigated. The results show that the TMAH textured surfaces with PS formation present a dramatic decrease in reflectance. The longer the anodizing time is, the lower the reflectance. Moreover, an initial surface with bigger pyramids achieved lower reflectance in a short wavelength range. A minimum reflectance of 3.86% at 460 nm is achieved for a short anodizing time of 2 min. Furthermore, the reflectance spectrum of the sample, which was etched in 3 vol.% TMAH for 25 min and then anodized for 20 min, is extremely flat and lies between 3.67% and 6.15% in the wavelength range from 400 to 1040 nm. In addition, for a short anodizing time, a slight increase in the effective carrier lifetime is observed. Our results indicate that PS layers formed on a TMAH textured surface for a short anodization treatment can be used as both broadband antireflection coatings and passivation layers for the application in solar cells.