Correlation Between Minority Carrier Diffusion Length and Microstructure in a-Si:H Thin Films

Abstract

Aim of this work is to investigate the opto-electronic properties of amorphous hydrogenated silicon (a-Si:H). The deposition temperature nas been used as a driving force to modify the morphology and bonded hydrogen distribution. The influence of the hydrogen microstructure on the carriers μτ product has been examined. The majority and minority carrier μτ have been evaluated from the diffusion length measurement, by using the Steady State Photocarrier Grating (SSPG) technique, and from the photoconductivity in the steady state condition (SSPC). The μτ values have been correlated with the defect density and the Fermi level position. Some considerations are proposed to explain the carrier transport in terms of the compositional inhomogeneities in Si:H alloys due to the morphological variations.