Shape and Size Controlled Deposition of ZnO Thin Films: Comparative Sensitivity towards Methane Gas

Abstract

The effect of different solutes and solvents on the morphology of Galvanically deposited ZnO thin films is reported here. Hexagonal grains with c – axis orientation were obtained from aqueous Zn(NO3)2 bath (System A), whereas, the aqueous ZnSO4 bath (System B) yielded cages of ZnO flakes on the xy plane. Almost spherical grains with smaller sizes were obtained from the DMF bath of Zn(NO3)2 (System C). The highest average roughness (Ra) was shown by the flake like morphology (107.11 nm) and the lowest by the spherical one (16.82 nm). The value of Ra was 21.5 nm for System A. Surface roughness is responsible for adsorbing the test gas, one of the most important factors influencing the sensitivity. Same thing is reflected here by the deposited films for methane sensing. At 300 C, System B showed maximum efficiency (89 %) and the minimum was 69 %, as shown by System C. On the other hand, System A showed an inbetween value of efficiency of about 75 %. The response time at 300 C was also lowest for System B, whereas, System A & C showed similar values. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/34999