CuO-doped BSST thick film resistors for ppb level H_2S gas sensing at room temperature

摘要

An effort has been made to develop a heterojunction type CuO-(Ba_(0.8)Sr_(0.2))(Sn_(0.8)Ti_(0.2))O_3 (BSST) gas sensor which could detect an extremely small amount of H_2S gas at room temperature. The BSST solid solution was prepared mechanochemically. Copper was doped in the BSST ceramics by adding CuCl_2, followed by sintering at 550℃ for 2h. Sintering converts CuCl_2 into CuO. CuO is known to be p-type and BSST as an n-type semiconductor. Copper oxide grains in association with BSST form p-CuO-BSST heterojunctions. The thick films of CuO-BSST were prepared by screen-printing technique. The CuO-BSST heterojunction gas sensor is a new type gas sensor and has many advantages, such as low cost, simple processing, and convenient testing. This sensor was observed to be highly sensitive and selective to a ppb level of H_2S gas at room temperature.