Temperature Dependence of the Resistance of AlGaN/GaN Heterostructures and Their Applications as Temperature Sensors

AlGaN/GaN heterostructures with a two-dimensional electron gas (2DEG) exhibit unique transport properties that could potentially be used for novel applications that are not related to conventional modulation-doped field effect transistor devices. Here, we describe the fabrication of high sensitivity temperature sensors exploiting temperature induced resistance changes of AlGaN/GaN-2DEG heterostructures. We observed a monotonous change in the resistance of the 2DEG from 3 to 1000 K. The temperature dependence of the resistance above 180 K fitted the Callender–Van Dusen equation. The sensitivity of the AlGaN/GaN temperature sensors was more than 2 times higher than conventional resistance temperature detectors near room temperature and 5 times higher at about 900 K. These new AlGaN/GaN temperature sensors may find niche applications in extreme environments, such as space exploration, as well as where high sensitivity is required over wide temperature ranges.