Improved Efficiency in Hydrogenated Amorphous Silicon Solar Cells Irradiated by Excimer Laser

Abstract

Excimer laser crystallisation is used to fabricate nanocrystalline thin film silicon Schottky barrier solar cells, in a superstrate configuration with indium tin oxide as the front contact and chromium as the back contact. 150 nm thick intrinsic absorber layers are used for the solar cells, and was crystallised using an excimer laser with different laser energy densities. These layers were characterised using Raman spectroscopy and optical absorption before device fabrication. External quantum efficiencies of the devices were calculated from the spectral response data of the devices. A maximum efficiency of 70 % is observed for low energy irradiation, which is significant for very thin absorber layers. Device operation is discussed with proposed band structures for the devices and supplementary measurements.