Ultra-high field transport in GaN-based heterostructures

Abstract

This paper describes measurements of the velocity of electrons at electric fields up to 100 kV/cm in GaN/AlGaN heterostructures. In order to avoid the Joule heating effect, a pulse technique with a time sweep of 10-30 ns was used. The experimental results indicate that overheating of the 2DEG does not exceed 1000 K in this electric field range and drift velocity as high as ~10⁷ cm/s was obtained. Additionally, the low frequency 1/f noise spectra measured for a different bias voltage are analyzed with respect to field-induced contribution of hopping conductivity in AlGaN barrier region.