Investigation of Passivation Films for a-Si Photoreceptors (Ⅰ)

—Properties of a-Si_1-xC_x: H films—

Abstract

Amorphous Si_1-xC_x: H films for passivation of a-Si photoreceptor have been prepared by reactive RF sputtering method using Si target in a gas mixture of Ar+60% H₂ and ethylene or methane.
The properties of films such as the resistivity, the optical bandgap, the spin density and the content of H atoms bonded to Si and C atoms are not different between the films prepared by these carbon sources.
The high resistivity (∼10¹⁵ Ω·cm) and the wide optical bandgap (∼2.6 eV) have been obtained at the carbon content X=0.4∼0.45. The content of H atoms bonded to Si atoms decreases rapidly with X in the range of 0.2, on the other hand the content of H atoms bonded to the C atoms increases monotonously with X. By XPS analysis, the ratios of O_1s/Si_2p at the surface of a-Si_1-× C_x: H films decrease with X. The difference of contact angle of water drop before and after oxidation test (60°C×80% RH×18 h) is relatively small in the films with the carbon content in the range of X>0.3.