Terahertz electroluminescence of shallow impurities in AlGaN/GaN heterostructures at 20 K and 110 K temperature

Abstract Terahertz (THz) electroluminescence of shallow impurities in the AlGaN/GaN HEMT structures grown either on sapphire or silicon carbide substrates were studied in this work. The radiative electron transitions 2 p − 1 s in the oxygen and silicon donors as well as additional c − 1 s transitions in the carbon atoms also were identified by THz emission spectroscopy at the temperatures of 110 K and 20 K, respectively. Moreover, the thermal quenching effect of the THz electroluminescence signals was found to occur at much higher electrical powers that were injected in the HEMT structures grown on silicon carbide as compared to that grown on the sapphire substrate.