Electrical and optical properties of doped p-type GaN superlattices

摘要

A comparison is reported of the electrical, photoelectrical, and microcathodoluminescence properties of bulk p-GaN films and p-type p-GaN(Mg)/GaN superlattices grown by molecular beam epitaxy. It is shown that the microcathodoluminescence intensity is much lower and the photocurrent (both on samples with indium Ohmic contacts and on Au Schottky diodes) much higher for the doped superlattices due to the spatial separation of photoexcited electrons and holes in the doped and undoped layers and corresponding increase of the lifetime in comparison to the bulk samples. The in-plane conductivity in the doped superlattices is not enhanced significantly relative to conventional p-GaN, but the hole mobilities are increased (from 12 to 20 cm~2/V s).