4H-SiC pn Photodiodes with Temperature-Independent Photoresponse up to 300 $^{\circ}$C

4H-SiC pn photodiodes were fabricated and the temperature dependence of the photoresponse was measured for various wavelengths (280–365 nm) as a function of reverse-bias voltage. A temperature-independent photoresponse was obtained at 280 nm illumination from room temperature to 300 °C under zero-bias condition. By applying reverse-bias voltage up to 150 V, the wavelength of the temperature-independent photoresponse was varied from 280 to 300 nm. The temperature-independent photoresponse was explained by the temperature dependence of optical absorption coefficient together with surface recombination effect.