Optical anisotropy of (112¯3) semipolar InGaN quantum wells homoepitaxially grown on GaN substrates

Abstract

InGaN/GaN quantum wells (QWs) are homoepitaxially grown on (112¯3) GaN substrates, and atomically smooth surfaces and abrupt InGaN/GaN interfaces are achieved. The optical anisotropy is examined using photo- and electroluminescence spectroscopies. Both methods consistently show in-plane optical polarization along the direction parallel to the projection of the c-axis on the QW plane. This polarization direction is rotated by 90° from that of unstrained, bulk InGaN, demonstrating the occurrence of polarization switching in strained, semipolar InGaN QWs. Specifically, the polarization direction is [1¯1¯22], which offers an advantage in that the {11¯00} m-planes can be used as cavity mirrors in edge-emitting lasers. The previously proposed analytical equation reasonably reproduces the experimental results.