Determination of localized conduction band-tail states distribution in single phase undoped microcrystalline silicon

TL;DR

This study investigates the distribution of conduction band-tail states in microcrystalline silicon by analyzing photoconductivity, revealing how microstructural differences influence electronic states and transport properties.

Contribution

It introduces a method to estimate localized tail states distribution in microcrystalline silicon using photoconductivity measurements and band-tail parameter calculations.

Findings

Different microstructures lead to varied phototransport behaviors.

The density of states maps correlate with microstructural attributes.

Band-tail states distribution can be quantified from photoconductivity data.

Abstract

We report on the phototransport properties of microstructurally well characterized plasma deposited highly crystallized microcrystalline silicon films. The steady state photoconductivity was measured on a wide microstructural variety of single-phase undoped microcrystalline silicon films as a function of temperature and light intensity. The band-tail parameter (kTc) was calculated from the photoconductivity light intensity exponent values at different temperatures for a range of quasi-Fermi energies. The localized tail states distribution in the vicinity of conduction band edge of microcrystalline silicon was estimated using the values of kTc. Our study shows that microcrystalline silicon films possessing dissimilar microstructural attributes exhibit different phototransport behaviors, which are linked to different features of the density of states maps of the material.