Tunneling in dislocation-free GaN/AlGaN double-barrier diodes grown on bulk GaN

Abstract

We report on negative differential resistance of a AlGaN‐GaN‐AlGaN double barrier. Using inductively coupled plasma reactive ion etching, 6 μm square mesas have been fabricated on 0001 GaN substrates derived from bulk GaN crystals grown at high pressure. Double barrier and n+ contact layers were grown Ga face using plasma assisted molecular‐beam epitaxy. We obtain peak currents around 10 kA/cm2 and a peak‐to‐valley ratio of about 2 at room temperature, while no improvement was observed at cryogenic temperatures. The drop in current does not depend on specific conditions of measurement; however, it slowly decays after each measurement. Partial recovery by thermal treatment was possible.