Deposition of nanocrystalline ZnO thin films on p-Si by novel galvanic method and application of the heterojunction as methane sensor

Undoped nanocrystalline n-ZnO thin films were deposited by a novel galvanic technique at room temperature on p-Si 〈100 〉 substrates to fabricate ZnO–Si heterojunctions. The I–V characteristics were studied at different temperatures with two different metallic contacts e.g., gold and palladium–silver (26%), in air and in presence of different concentrations (0.1, 0.5 and 1%) of methane gas. A shift in I–V characteristics in presence of methane was observed. The sensitivity and response time were studied at different temperatures (30 through 350 °C). Pd–Ag (26%) catalytic contacts showed much improved sensor performance.