AIGaN/GaN HEMT sub-bands study using low-temperature photoluminescence

Abstract

Al0.1Ga0.9N/GaN HEMTs (High Electron Mobility Transistor) structures with different delta-doping concentration and spacer thickness grown on sapphire by MOCVD are studied. The hall mobility is as high as 1333 cm(2)/V s. at room temperature and 6330 cm(2)/V s at 77 K. Obvious 2-DEG phenomena not clearly resolved in literatures before are observed by PL spectra measured at low temperature. The influences of delta-doping concentration and spacer thickness on the 2-DEG phenomena are discussed. Peaks red-shift of different HEMT structures due to temperature variation are observed in 2-DEG sub-bands as well as at the band-edge emission that is believed as a strong evidence of 2DEG sub-bands to valence bands transmission.