Electronic properties and structure of a-Si : H films with higher photosensitivity

The temperature dependences of the photoconductivity, the Urbach parameter, the optical modulation spectra, and the Raman spectra were studied in orde r to determine the cause of the increase in photosensitivity of a-Si : H fi lms. It is shown that these films combine a low defect density with the exi stence of deep hole capture centers. These factors increase the value of si gma(ph) at T=300 K in comparison with the sigma(ph) of standard a-Si : H, w ith Delta E=const. (C) 1999 American Institute of Physics. [S1063-7826(99)0 1703-2].