Carrier dynamics and electrostatic potential variation in InGaN quantum wells grown on {112¯2} GaN pyramidal planes

Abstract

InGaN quantum wells grown in the conventional [0001] direction are known to exhibit long carrier lifetimes that are attributed to strong internal electric fields due to spontaneous and piezoelectric polarization. These fields are expected to be considerably reduced in other crystal geometries. In this work, the authors have investigated the carrier dynamics of InGaN single quantum wells grown parallel to {112¯2} planes. The carrier lifetimes, measured by time-resolved cathodoluminescence, are considerably smaller than for quantum wells grown in the conventional c-plane geometry. In addition, the lifetime does not change significantly with varying indium composition or increasing well width. Electron holography measurements of the electrostatic potential across these quantum wells confirm that the internal fields in this geometry are negligible. These results are of interest for the development of higher-efficiency light-emitting diodes using alternative substrate orientations.