Amorphous hydrogenated silicon films exhibiting enhanced photosensitivity

Abstract

Amorphous hydrogenated silicon (a-Si:H) films with photoconductivities as high as 106, i.e., exceeding the photoconductivity of “standard” a-Si:H by two orders of magnitude, are investigated. The dark conductivity (σ d ) of the films has an activation energy ΔE=0.85–1.1 eV. The photoconductivity σ ph is measured at a photocarrier generation rate of 1019 cm−3 · s−1 and photon energy ɛ=2 eV. Several distinctive characteristics are ascertained in the behavior of σ ph and σ d as functions of ΔE and also in the spectral curve and decay kinetics of σ ph during prolonged illumination. It is concluded that the investigated material holds major promise for photovoltaic device applications.