ZnO/a-Si Distributed Bragg Reflectors for Light Trapping in Thin Film Solar Cells from Visible to Infrared Range

TL;DR

This paper demonstrates that ZnO/a-Si distributed Bragg reflectors, fabricated via magnetron sputtering, effectively enhance light trapping and photocurrent in thin film solar cells across visible to infrared wavelengths.

Contribution

It introduces a novel ZnO/a-Si DBR design with high reflectance and broad stopband, improving light trapping in thin film solar cells.

Findings

ZnO/a-Si DBRs achieve >99% peak reflectance.

Broader stopband from 686 nm to 1354 nm with combined DBRs.

Significant increase in photocurrent compared to Al reflector.

Abstract

Distributed bragg reflectors (DBRs) consisting of ZnO and amorphous silicon (a-Si) were prepared by magnetron sputtering method for selective light trapping. The quarter-wavelength ZnO/a-Si DBRs with only 6 periods exhibit a peak reflectance of above 99% and have a full width at half maximum that is greater than 347 nm in the range of visible to infrared. The 6-pair reversed quarter-wavelength ZnO/a-Si DBRs also have a peak reflectance of 98%. Combination of the two ZnO/a-Si DBRs leads to a broader stopband from 686 nm to 1354 nm. Using the ZnO/a-Si DBRs as the rear reflector of a-Si thin film solar cells significantly increases the photocurrent in the spectrum range of 400 nm to 1000 nm, in comparison with that of the cells with Al reflector. The obtained results suggest that ZnO/a-Si DBRs are promising reflectors of a-Si thin-film solar cells for light trapping.