【摘要】 AlGaN/GaN高电子迁移率晶体管（HEMT）已被广泛应用于氢气、氨气和硫化氢等气体传感器的开发，但针对二氧化碳（CO₂）气体的AlGaN/GaN HEMT传感器研究仍相对较少.采用物理涂覆法将聚乙烯亚胺（PEI）功能化AlGaN/GaN HEMT的栅极表面，构建了PEI-HEMT传感器用于CO₂检测.在室温条件下，该传感器可实现2%～15%浓度CO₂的检测.随着环境湿度升高，其对CO₂的响应灵敏度增强，基线漂移减小，但响应速度有所下降.由于物理涂覆的PEI层易发生脱落，PEI-HEMT传感器的长期稳定性较差.为此，进一步采用烷基偶联法通过戊二醛（GA）将PEI化学桥接于栅极，制备出PEI-GA-HEMT传感器.该结构表现出较PEI-HEMT更慢的CO₂响应速度，但具有良好的重复性与长期稳定性，检测范围也更宽，最低可检测至0.05%浓度的CO₂.更多还原

【Abstract】 AlGaN/GaN high electron mobility transistors（HEMT） are widely used in the development of gas sensors for hydrogen, ammonia and hydrogen sulfide, but research on AlGaN/GaN HEMT sensors for carbon dioxide（CO₂） gas remains relatively limited. The gate surface of the AlGaN/GaN HEMT is functionalized with polyethylenimine（PEI） via physical coating, constructing a PEI-HEMT sensor for CO₂ detection. At room temperature, this sensor can detect CO₂ concentrations ranging from 2% to 15%. As the ambient humidity increases, its sensitivity to CO₂ enhances, the baseline drift decreases, but the response speed slows down. Since the physically coated PEI layer is prone to detachment, the long-term stability of the PEI-HEMT sensor is poor. Therefore, an alkyl coupling method is further employed to chemically bridge PEI to the gate via glutaraldehyde（GA）, resulting in the fabrication of a PEI-GA-HEMT sensor. This structure exhibits a slower CO₂ response speed compared to the PEI-HEMT, but demonstrates good repeatability and long-term stability, and a wider detection range, with a minimum detectable CO₂ concentration of 0.05%.更多还原