Sensitivity Enhancement of Atomic-layer MoS2 Gas Sensor Through Oxygen Plasma Treatment
Date Issued
2016
Date
2016
Author(s)
Pan, Kuan-Hsun
Abstract
A novel volatile organic compound (VOC) sensor with the MoS2 atomic-layers was developed in this research. Such sensor was made by transferring the MoS2 atomic-layers grown with the chemical vapor deposition (CVD) method onto the interdigitated electrode manufactured by microelectromechanical systems for indicating the sensing ability by the impedance change. The density of defects on the MoS2 film surface was controlled by the ratio of precursors and surface treatment. The sensing mechanism related to surface defects created was illustrated using the photoluminescence spectrometer. The surface defects were found to be increased with the increasing oxygen plasma treatment (OPT) cycles due to the increase of surface defects. An optimized number of OPT cycles was found to get the excellent gas detection performance. The treated MoS2 gas sensor exhibited the good performance, sensing range, and repeatability. The chemical compounds operated at different temperatures and intensity of light power were also observed. Traditional gas sensors utilizing metal oxide as the sensing material were typically equipped with a heater. Although the gas adsorption and desorption were increased by incorporating a heater, one more photo-masking and additional processing were required to define the heater. With the high temperature heating, it’s not desirable to integrate with CMOS-based circuits and use in explosive environment. In this work, we developed a MoS2-based gas senor which can detect methanol with high sensitivity at room temperature without the extra light-activation and react with many kinds of VOCs. Based on the structure of gas, the gas sensor has the different response that shows a great potential to the environment detection.
Subjects
gas sensor
molybdenum disulfide
light active
photoluminescence
oxygen plasma treatment
Type
thesis
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