Amorphous hydrogenated silicon films exhibiting enhanced photosensitivity

Amorphous hydrogenated silicon (a-Si:H) films with photoconductivities as h igh as 10(6), i.e., exceeding the photoconductivity of "standard'' a-Si:H b y two orders of magnitude, are investigated. The dark conductivity (sigma(d )) of the films has an activation energy Delta E=0.85 -1.1 eV. The photocon ductivity sph is measured at a photocarrier generation rate of 10(19) cm(-3 ).s(-1) and photon energy epsilon=2 eV. Several distinctive characteristics are ascertained in the behavior of sigma(ph) and sigma(d) as functions of Delta E and also in the spectral curve and decay kinetics of sigma(ph) duri ng prolonged illumination. It is concluded that the investigated material h olds major promise for photovoltaic device applications. (C) 1999 American Institute of Physics. [S1063-7826(99)02301-7].