Direct measurement of hot-carrier generation in a semiconductor barrier heterostructure: Identification of the dominant mechanism for thermal droop

Energy measurements of electrons emitted from a semiconductor can reveal internal physical processes hitherto elusive. Signatures of hot-electron processes in heterostructures have been observed from cesiated, light-emitting, and p-i-n diodes. In p-i-n devices with AlGaN barriers, a high-energy peak was measured and ascribed to a trap-assisted Auger recombination process. Temperature dependent measurements of light-emitting diodes with AlGaN electron blocking layers also show such hot carriers when electrons thermally reach these barriers, identifying carrier escape as the mechanism of thermal droop and demonstrating the efficacy of such barriers to partially mitigate thermal droop.