Characteristics of Hydrogen Sensors Based on Anocrystalline Thin Films of Tin Dioxide with Various Complex Modifiers

Abstract

Results of investigation of the effect of the complex modifiers of silver and yttrium introduced into bulk of tir dioxide thin films with disperse layers of Pt/Pd on the surface or the properties of hydrogen sensors are presented in this work The thin films of tin dioxide were obtained by magnetror sputtering of tin - antimony alloy target at the direct current The influence of humidity on the electrical and gas-sensitive characteristics of the hydrogen sensors based on these films wa: investigated. The long-test stability of the investigated samples was researched. It is shown that additives silver and yttrium in the presence of Pt/Pd on the surface provide the maximum values of the response to hydrogen at 670 K. In the cases of the depositec catalytic silver the response to hydrogen is considerably lower. II according with the results of the experiments, the characteristics of the films with additions of silver+yttrium in the bulk have weaker dependence on humidity changes. A common feature of samples with modifiers of silver and yttrium is the high stability of their properties under the periodical influence of hydrogen in long-term tests. Analysis of results shown that the complei modifiers of silver+yttrium interact with lattice atoms of tin and oxygen contribute to the emergence of deep centers in the semiconductor, and these additives prevent the process o reduction of tin dioxide at hydrogen adsorption and ensure the stability of the parameters of the sensors in operation.