Control of optical polarization properties by manipulation of anisotropic strain in nonpolar m-plane GaInN/GaN quantum wells

Abstract

We report on the control of optical polarization properties of nonpolar m-plane Ga1–xInxN/GaN quantum wells by manipulation of anisotropic in-plane strain via the insertion of a partially relaxed AlInN interlayer prior to the quantum wells. Structures with different interlayer compositions are compared to m-plane quantum wells without interlayers as reference. With these interlayers, we are able to either decrease or increase the strain in the quantum wells, as well as change the strain in just one in-plane direction to further change the anisotropy of strain. This results in a modified valence band structure which strongly influences optical properties such as the degree of optical polarization. Systematic evaluation of the polarization splittings opens up the opportunity to experimentally determine the deformation potential D5 for different anisotropic strain states for indium contents between 13% and 37%, which provides a good estimate for D5 for InN. Finally, we compare the measurements to k ⋅ p calculations, using the deformation potential derived from the experiments.