Defect formation in GaN epitaxial layers due to swift heavy ion irradiation

Abstract

GaN epitaxial layers were irradiated with 200 MeV Ag ions at various fluences. These samples were characterized ex situ by resistivity/Hall, XRD, and transmission electron microscopy (TEM). The resistivity of irradiated layers increased by eight orders of magnitude after irradiation with a fluence of 5×10¹² ions/cm². The increase in peak width (FWHM) with the incident ion fluence showed a reduction in the crystallinity of epitaxial layers. Cross-sectional TEM images confirmed that at the highest fluence (5×10¹² ions/cm²), electronic energy loss caused structural defect formation in the GaN layer.

Keywords:

• GaN
• swift heavy ions
• defects
• XRD
• hall/resistivity
• TEM

Acknowledgements

Mr Ashish Kumar would like to gratefully acknowledge the University Grant Commission (UGC) for providing a research fellowship. We are thankful to Dr R. Scholz from the Max Planck Institute for Microstructure Physics, Halle, Germany, for performing TEM measurements.