Gas Sensing Properties of ZnO Thin Film/Si Heterojunction to Alcohols
The polycrystalline zinc oxide (ZnO) film was deposited on p-Si substrate by radio-frequency (RF) magnetron sputtering. The structure and morphology of the ZnO thin films are characterized by X-ray diffraction (XRD), the energy dispersive analysis of X-ray (EDX) and scanning electron microscope (SEM). The gas sensing properties of the ZnO/Si heterojunctions for alcohols with different chain lengths were investigated at room temperature. It is found that the current-voltage (I-V) characteristics of the ZnO/Si heterojunctions are sensitive to isopropanol, ethanol and methanol gas. We discussed a possible gas sensing mechanism of ZnO/Si heterojunction. The sensitivity of the ZnO/Si heterojunctions to the gases decreases from isopropanol to methanol and to ethanol at the same concentration. It can be explained by the volume effect and electron donating effect.
Chengming Li, Chengbao Jiang, Zhiyong Zhong and Yichun Zhou
X. Y. Zhou et al., "Gas Sensing Properties of ZnO Thin Film/Si Heterojunction to Alcohols", Materials Science Forum, Vol. 687, pp. 798-802, 2011