用闪锌矿制备ZnS-ZnO异质结及其NO2气敏特性

将闪锌矿纯矿物通过焙烧工艺制备成ZnO前驱体,随后添加Na2S·9H2O实现对ZnO前驱体的硫化,从而制备出ZnS-ZnO异质结材料,采用XRD、SEM、FTIR等检测手段对其进行结构表征。结果表明,制备出的ZnS-ZnO异质结材料呈颗粒状,尺寸在80 nm左右,且具有较大的比表面积。ZnS-ZnO异质结材料对NO2气体具有良好的响应和恢复特性,并在工作温度250℃时获得最大灵敏度,且灵敏度与NO2气体浓度符合指数函数关系。在相同检测条件下,与单一ZnO材料相比,ZnS-ZnO异质结材料呈现出工作温度低、灵敏度高、响应和恢复时间短等优异特性。在ZnS与ZnO晶界处所形成的n-n型异质结结构是改善气敏特性的关键因素。

Preparation and NO2 sensing properties of ZnS-ZnO heterojunctions based on sphalerite

ZnS-ZnO heterojunctions were prepared by roasting pure sphalerite to ZnO precursor and subsequently adding Na2S 9H2O to complete sulfuration process.The structural characterizations were carried out by means of XRD,SEM,and FTIR.The results show that the ZnS-ZnO heterojunctions with particle size of about 80 nm has a high specific surface area.The ZnS-ZnO heterojunctions have excellent NO2sensing properties.The maximum response of the ZnS-ZnO heterojunctions is obtained at an operating temperature of 250℃with fast response and recovery speeds,and there is an exponential function relationship between the sensor response and NO2 concentration.Comparing with single ZnO materials,ZnS-ZnO heterojunctions have outstanding sensing properties such as lower peak operating temperature,higher response,and shorter response and recovery times.The formation of n-n heterojunction structure at the grain boundary of ZnS and ZnO is the key factor to improve the gas sensing properties.