磁控溅射SnO_(2)/ZnO复合纳米薄膜的气敏特性研究

Gas sensing property research of magnetron sputterting SnO_(2)/ZnO composite nano films

采用射频磁控溅射方法,在溅射气压为2.5 Pa时,在p-Si衬底上沉积氧化锡(SnO_(2))/氧化锌(ZnO)复合纳米薄膜。沉积过程中,SnO_(2)薄膜的沉积厚度固定为40 nm,通过改变ZnO薄膜的沉积厚度来改变SnO_(2)/ZnO的膜厚比。详细分析了工作温度和膜厚比变化对复合纳米薄膜气敏特性的影响。结果表明,SnO_(2)/ZnO复合纳米薄膜的最佳工作温度为350℃,与ZnO和SnO_(2)单层薄膜相比,复合纳米薄膜的气敏性能显著提升。当SnO_(2)与ZnO的膜厚比为4︰3时,其气敏性能最佳,在350℃下,对于5×10^(-6)乙醇气体的灵敏度最高可达4。该SnO_(2)/ZnO复合纳米薄膜气敏性能的提升归因于ZnO与SnO_(2)之间形成的n-n异质结。

SnO_(2)/ZnO composite nano films with different film thickness ratios are prepared on the p-Si substrate by RF magnetron sputtering with the sputtering pressure of 2.5 Pa.When the thickness of SnO_(2)nano film is fixed at 40 nm,the film thickness ratio of SnO_(2)/ZnO is controlled by changing the thickness of ZnO nano film.The effects of operating temperature and film thickness ratio on the gas sensing characteristics of composite nano films are analyzed in detail.The results show that the optimal operating temperature of SnO_(2)/ZnO composite nano films is 350℃.Compared with pure ZnO and SnO_(2)nano films,the gas sensing performance of composite nano films is significantly improved.When the film thickness ratio of SnO_(2)to ZnO is 4!3,its gas sensing performance is the optimal.In 350℃,the gas sensitivity to 5×10-6 ethanol gas is up to 4.The improvement of the gas-sensing performance of the SnO_(2)/ZnO composite nano film is attributed to the formation of n-n heterojunctions between ZnO and SnO_(2).