Measurements of the electron density in n-type a-Si: H

Abstract

The density of band tail electrons in n-type a-Si: H, at doping levels between 10⁻³ and 10⁻⁶ PH₃, has been measured using a transient-voltage technique on layered samples. At a doping level of 10⁻³ PH₃ a density of 8 × 10¹⁶ cm⁻³ is found which agrees well with ESR data. The results confirm that occupied band-tail states account for only a small fraction of the dopant electrons.