Akın Bacıoğlu

Electrical and optical properties of glow-discharge a-SiOx : H (x<2)

Hydrogenated amorphous silicon–oxygen alloy (a-SiOx : H) films were deposited by r.f. glow-discharge decomposition of a SiH4+CO2 gas mixture at a substrate temperature of 300 °C. The optical band gaps of the samples were found to change between 1.65 and 2.73 eV by varying the oxygen content from 4.5 to 64.2 at %. While both the room-temperature photo- and dark-conductivity decrease with oxygen alloying, for oxygen contents below 11.9 at % the measured conductivities are comparable to those of unalloyed a-Si : H. In contrast, the deep-defect density and Urbach parameter continuously increase with oxygen alloying.