Near-field study of optical modes in randomly textured ZnO thin films

被引：10

作者：

Bittkau, K. ^{[1
]}

Carius, R. ^{[1
]}

机构：

[1] Forschungszentrum Julich GmbH, Inst Photovoltaik, D-52425 Julich, Germany

来源：

SUPERLATTICES AND MICROSTRUCTURES | 2007年 / 42卷 / 1-6期

关键词：

near-field microscopy; thin-film solar cell; ZnO; random surface; light trapping;

D O I：

10.1016/j.spmi.2007.04.002

中图分类号：

O469 [凝聚态物理学];

学科分类号：

070205 ;

摘要：

We report on near-field scanning optical microscopy measurements on randomly textured ZnO thin films. These films are commonly used as transparent conducting oxide in thin-film solar cells. Textured interfaces are used to increase the scattering of light, which leads to a better light trapping in the solar cell. Here, both the topography and the local transmission are measured with a tapered fiber tip with very high spatial resolution. By varying the distance of the tip and the wavelength of the incident light, the optical profile is visualized and reveals a strong confinement of light on a subwavelength scale which corresponds to ridges in the surface structure. The confinement of light results from guided optical modes in the ZnO which are accompanied by a modulated evanescent field in air. No corresponding structure to this modulation is found in the topography. These results give new insight for further improvement of light trapping in solar cells. (c) 2007 Elsevier Ltd. All rights reserved.

引用

页码：47 / 51

页数：5

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