structural and optical properties of InxGa1-xN/GaN epilayers grown on a miscut sapphire substrate

TL;DR

This study investigates how a slight miscut in sapphire substrates affects the structural and optical properties of InGaN/GaN epilayers grown via MOCVD, providing detailed characterization of strain, composition, and emission.

Contribution

It presents a comprehensive analysis of miscut sapphire substrates' influence on InGaN/GaN epilayers, combining multiple advanced characterization techniques.

Findings

No strain anisotropy observed.

Precise measurement of lattice parameters and strain.

Effect of miscut on bandedge emission analyzed.

Abstract

We report on structural and optical properties of InGaN/GaN thin films, with a 0.46o misalignment between the surface and the (0001) plane, which were grown by metal-organic chemical vapor deposition (MOCVD) on 0.34o miscut sapphire substrates. X-ray diffraction and X-ray reflectivity were used to precisely measure the degree of miscut. Reciprocal space mapping was employed to determine the lattice parameters and strain state of the InGaN layers. Rutherford backscattering spectrometry with channeling was employed to measure their composition and crystalline quality with depth resolution. No strain anisotropy was observed. Polarization-dependent photoluminescence spectroscopy was carried out to examine the effect of the miscut on the bandedge emission of the epilayer.