In this work, a high-performance AlGaN-channel Schottky barrier diode with high breakdown voltage of 2.23 kV defined at anode leakage current of 1 μA and high power figure-of-merit of 614 MW/cm2 is demonstrated. Anode voltage (VA) with a clear linear relationship as a function of temperature from 300 to 525 K shows great potential for temperature sensors, and maximum temperature sensitivity of 2.0 mV/K at anode current density (IA) of 6.28 × 10−8 A is obtained, satisfying the low power consumption requirement. Meanwhile, the corresponding temperature sensitivity of ln(–I) vs temperature at a fixed VA of –15 V is 5.0 mA/K, and the suppressed temperature sensitivity at reverse bias is attributed to the energy-band modulated Schottky barrier height of AlGaN-channel M/S interface, which is vital for high-temperature and high-power applications.