Electron drift velocity in lattice-matched AlInN/AlN/GaN channel at high electric fields

Abstract

Hot-electron transport was probed by nanosecond-pulsed measurements for a nominally undoped two-dimensional channel confined in a nearly lattice-matched Al0.82In0.18N/AlN/GaN structure at room temperature. The electric field was applied parallel to the interface, the pulsed technique enabled minimization of Joule heating. No current saturation was reached at fields up to 180 kV/cm. The effect of the channel length on the current is considered. The electron drift velocity is deduced under the assumption of uniform electric field and field-independent electron density. The highest estimated drift velocity reaches ∼3.2×107 cm/s when the AlN spacer thickness is 1 nm. At high fields, a weak (if any) dependence of the drift velocity on the spacer thickness is found in the range from 1 to 2 nm. The measured drift velocity is low for heterostructures with thinner spacers (0.3 nm).