Enhanced ultraviolet to near-infrared absorption by two-tier structured silicon formed by simple chemical etching |
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| Authors: | Jing Jiang Yadong Jiang Zhiming Wu Zhanfei Xiao Yuanjie Su |
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| Affiliation: | State Key Laboratory of Electronic Thin Films and Integrated Devices , School of Optoelectronic Information, University of Electronic Science and Technology of China , 610054 Chengdu , China |
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| Abstract: | Two-tier structured silicon with micron/nanometre scale features is fabricated by simple wet chemical etching. The structured silicon sample exhibits dramatically enhanced absorption from ultraviolet to near-infrared wavelength (250–2500?nm). Absorption is enhanced to near unity at wavelengths shorter than 1100?nm caused by the extremely suppressed reflection from the two-tier structured surface. Within the wavelength range from 1100 to 2500?nm, the sample exhibits a strong absorbance of 69.6% at 1100?nm and an average of 30% at longer wavelengths. By analyzing XPS spectra from the surface of the two-tier structured sample, we attribute this near-infrared absorption to band structure and morphological changes presented in the textured layer. |
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| Keywords: | two-tier roughness wet chemical etching enhanced absorption bandgap |
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