Band to band recombination peak in the light emission of commercial pseudomorphic HEMTs

Pseudomorphic HEMTs are studied in the impact ionization regime by measuring the energy distribution of the emitted photons. A sharp light intensity peak around 1.2-1.3 eV is observed; both its position and temperature dependence indicate that the peak can be ascribed to recombination of electrons sitting on the bottom of the conduction band with holes at the top of the valence band. Quasi-Maxwellian distributions with high equivalent temperature are observed at higher energies.