이황화 몰리브덴을 이용한 이산화탄소 감지 센서에 관한 연구

Abstract

Study on Carbon Dioxide Detection Sensors using Molybdenum Disulfide Hyun-sik Shin Advisor : Prof. Min Ki Kwon, Ph.D. Department of Photonic Engineering Graduate School of Chosun University In this study, we proposed, investigated, and evaluated the development of a CO2 gas sensor made of functional nanomaterials to monitor CO2 gas emitted during human respiration. We used two-dimensional nanomaterials as a process to improve the performance of gas sensors, found conditions in the environment that could be variables in the performance of the sensor, and used the processes of sputtering (PVD) and hydrothermal synthesis. By comparing and analyzing the proposed sensors, the capabilities of the gas sensor were evaluated through various variable conditions (ratio, temperature, time, doping, and wavelength). Through the doping process, the sensitivity of the 2D TMDc-based gas sensor was improved by changing the bandgap of the existing MoS2 material, and the difference in response time and current value when a wavelength was applied under carbon dioxide conditions was improved. Finally, a sensor based on Au/Nb/MoS2 was manufactured, and the wavelength was applied to a non-contact CO2 material to improve sensitivity and expand the responsiveness of the sensor. These results show that MoS2-based sensors of 2D TMDc materials will be used in the future. It shows that it can be expanded by being applied to various industrial fields, optical and agricultural sensors The chemical sensing applications of IoT have garnered significant attention for the real-time detection of environmental pollutants, which is crucial not only for the medical diagnosis of various diseases but also for taking preventive measures. Although diverse sensor types have been developed and implemented, they often face challenges such as slow responsiveness, limited detection ranges, chemical instability, bulky sizes, high power consumption, and persistently high costs. Recently, 2D nanomaterials with semiconductor characteristics, such as TMDs (Transition Metal Dichalcogenides), have emerged as an alternative solution. Their attributes including low power consumption, high mobility of charge carriers, lightweight nature, high stretchability, reliable mechanical strength, excellent optical transparency, and outstanding environmental stability make them excellent candidates for flexible devices. Particularly, the large surface-to-volume ratio of 2D materials has gained attention in chemical sensing applications. However, there's been substantial research on highly reactive gases like moisture, ammonia, and NO2. In contrast, there's a scarcity of research concerning the detection of carbon dioxide (CO2), which is highly demanded in various fields like healthcare, air purification, and smart agriculture. In this study, we aimed to enhance the performance of CO2 sensors utilizing the 2D nanomaterial MoS2. We grew MoS2 thin films using various synthesis methods such as sputtering (PVD) and hydrothermal synthesis, and endeavored to improve reactivity through various process parameter conditions (ratios, temperatures, times, doping). These outcomes demonstrate the potential utilization of MoS2-based sensors using 2D TMDc materials for CO2 detection across various fields. This suggests the possibility of extending their application not only to diverse industrial sectors but also to optical and agricultural sensors.