Amorphous hydrogenated silicon films exhibiting enhanced photosensitivity

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 (σd) of the films has an activation energy ΔE=0.85–1.1 eV. The photoconductivity σph 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 σph and σd as functions of ΔE and also in the spectral curve and decay kinetics of σph during prolonged illumination. It is concluded that the investigated material holds major promise for photovoltaic device applications.