Extensive analysis of the luminescence properties of AlGaN/GaN high electron mobility transistors

This paper reports on an extensive analysis of the electroluminescence spectra of GaN-based high-electron mobility transistors (HEMT) submitted to different bias regimes. The results described within this paper indicate that: (i) under ON-state bias conditions, HEMT can emit a weak luminescence signal, localized at the edge of the gate toward the drain side; (ii) for low drain voltage levels, the electroluminescence spectrum has a Maxwellian shape, which is typical for hot carrier luminescence; (iii) for high drain voltage levels, parasitic emission bands are generated, possibly due to the recombination of hot electrons through defect-related sites. Electroluminescence data are compared with results of cathodoluminescence measurements, to provide an interpretation for the experimental results.