Ozone sensing properties of DC-sputtered, c-axis oriented ZnO films at room temperature
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- 作者：Katsarakis ; N. ; Bender ; M. ; Cimalla ; V. ; Gagaoudakis ; E. ; Kiriakidis ; G.
- 关键词：Zinc oxide ; Ozone ; Sensors ; Surface conductivity
- 刊名：Sensors and Actuators B: Chemical
- 出版年：2003
- 出版时间：November 15, 2003
- 年：2003
- 卷：96
- 期：1-2
- 页码：76-81
- 全文大小：258 K
文摘
Polycrystalline zinc oxide films with a thickness of 150 and 1000nm were deposited on Corning 7059 glass and Silica substrates at various substrate temperatures ranging from room temperature (RT) to 400°C. The optical band gap of the films was found to be strongly dependent on the deposition temperature, e.g. it decreased with increasing temperature. Both the 150 and 1000nm-thick films showed a preferred growth orientation along the c-axis when deposited at T<200°C, though the effect was more pronounced for the thicker films. At higher deposition temperatures, the films showed rather a random crystallite orientation even though the (002) reflection always displayed the higher intensity. ZnO films with a thickness of 150nm, which were deposited at room temperature exhibited the highest sensor response to ozone after repeated photoreduction–oxidation cycles, namely ![]()
enter border=0 SRC=/images/glyphs/BQ1.GIF>106, in comparison with the 1000nm-thick films which exhibited a maximum sensor response of ![]()
enter border=0 SRC=/images/glyphs/BQ1.GIF>103 when deposited at room temperature. The conduction mechanism is discussed in terms of an ultra-thin surface layer, which is mainly contributing to the photoconductivity in polycrystalline ZnO films.