Paper TF-WeP25
Investigation of CO₂ Sensing Efficiency and Mechanism Based on P-type MoS₂

Wednesday, December 5, 2018, 4:00 pm, Room Naupaka Salon 1-3

Two-dimensional materials have attracted tremendous attention die to their unique electronic structures, as well as extraordinary physical and chemical properties for sensing gas. In this work, we investigated the CO₂ sensing efficiency and sensing mechanism based on P-type MoS₂ which was doped with niobium (Nb). With a relatively high Nb dopant concentration, the sensor response showed decreased sensitivity, which could be attributed to a higher metallic NbS₂ ratio in the semiconducting MoS₂ film. Using in-situ x-ray absorption spectroscopy (XAS) and ambient-pressure x-ray photoelectron spectroscopy (ARXPS) techniques at national synchrotron radiation research center (NSRRC), we found that CO₂ acted as electron acceptor. However, the resistance of P-type MoS₂ would increase in sensor measurement, which was different from charge-transfer mechanism that acceptors would lower down the resistance of p-type semiconductor. The different behaviors between spectrum results and electric measurements may be the result of different sensing mechanism. The dominated mechanism in this research could be intercalation mechanism which gas molecules intercalated into the structure and changed the conducting path. This work was financially supported by the “Center for the Semiconductor Technology Research” from The Featured Areas Research Center Program within the framework of the Higher Education Sprout Project by the Ministry of Education (MOE) in Taiwan. Also supported in part by the Ministry of Science and Technology, Taiwan, under Grant MOST-107-3017-F-009-002.