Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/134990
Title: STUDY OF GATE VOLTAGE STRESS AND VISIBLE LIGHT IRRADIATION ON MOS2 BASED GAS SENSORS
Authors: TONG YU
Keywords: MoS2, Gas Sensors, Gate Voltage Stress, Photoresponse
Issue Date: 17-Aug-2016
Source: TONG YU (2016-08-17). STUDY OF GATE VOLTAGE STRESS AND VISIBLE LIGHT IRRADIATION ON MOS2 BASED GAS SENSORS. ScholarBank@NUS Repository.
Abstract: MoS2 is one of the most promising 2-D materials and has been intensively investigated. The ultra-thin nature makes MoS2 extremely sensitive to environmental perturbations such as adsorption of gas molecules. The thesis studies MoS2 based gas sensors and how gate voltage stress and light irradiation affect the sensor performances. Firstly, it is found that the gate voltage stress is effective in enhancing gas adsorption/desorption on MoS2. Applying a positive gate voltage stress can enhance the sensor response while applying negative gate voltage stress can achieve a fast and full recovery at room temperature. Following that, a time constant spectrum method is proposed to sense selectively and distinguish different gas species based on gate voltage stress induced gas adsorption and desorption. By decomposing the transient current responses after gate voltage stress into multiple exponential decaying terms, the analysis can distinguish different gas species associated with exponential terms of different time constants. Based on the time constant spectrum analysis, MoS2 based gas sensor is able to detect O2, water vapor, and ethanol respectively. Further investigation of the effect of light irradiation on MoS2 gas sensing behaviors is conducted and a photosensor to distinguish wavelength of incoming light based on the light irradiation induced gas desorption is demonstrated. It is demonstrated that visible light irradiation would compromise the sensing response, while it enhances the sensor recovery dramatically.
URI: http://scholarbank.nus.edu.sg/handle/10635/134990
Appears in Collections:Ph.D Theses (Open)

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