TEM and XANES study of MOVPE grown InAIN layers with different indium content

Abstract

We present structure and spatially resolved composition studies by TEM (Transmission Electron Microscopy) and XANES (X-ray Absorption Near Edge Structure) of InAIN MOVPE (Metal-Organic Vapor Phase Epitaxy) epilayers containing 16-27 at% of indium. Investigations of the In L3 edge by synchrotron radiation absorption show a significant change of the post-edge structure depending on the indium content. We attribute this to the solubility limit and phase separation in this system. Our measurements suggest that the critical composition is 18% for our growth conditions. HRTEM cross-sectional and EDX investigations confirm such phase separation as well as the changing of the structure from 2D growth to columnar like growth for the sample with the highest indium content.