Damage to epitaxial GaN layer on Al2O3 by 290-MeV 238U32+ ions irradiation

L Q Zhang; C H Zhang; J J Li; Y C Meng; Y T Yang; Y Song; Z N Ding; T X Yan

doi:10.1038/s41598-018-22321-w

Damage to epitaxial GaN layer on Al₂O₃ by 290-MeV ²³⁸U³²⁺ ions irradiation

Sci Rep. 2018 Mar 7;8(1):4121. doi: 10.1038/s41598-018-22321-w.

Authors

L Q Zhang^{1

2}, C H Zhang³, J J Li^{1

2}, Y C Meng^{1

2}, Y T Yang¹, Y Song¹, Z N Ding¹, T X Yan^{1

2}

Affiliations

¹ Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000, China.
² University of Chinese Academy of Sciences, Beijing, 100049, China.
³ Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000, China. c.h.zhang@impcas.ac.cn.

Abstract

Micro-structural characteristics and electrical properties of an n-type GaN epilayer on Al₂O₃ irradiated by 290-MeV ²³⁸U³²⁺ ions to various fluences were investigated using atomic force microscopy (AFM), scanning electron microscopy (SEM), high-resolution X-ray diffraction (HRXRD), and Raman scattering spectroscopy. AFM images show that the nano-hillocks generated, and the diameter and density of the nano-hillocks, increase obviously with increasing ion fluence, accompanied by an increase in surface roughness. SEM images display that the Al, O, and C elements appear on the GaN surface, along with a spiral-like, layered volcanic-cone structure formed at the highest-fluence irradiation. HRXRD reveals that the dislocation density increases, as the lattices gradually expand, and that Ga₂O₃ was produced with increasing ion fluence. Raman scattering spectra show that no N and Ga vacancies were produced, the free-carrier concentration decreases, while its mobility first increases and then exhibits a significant reduction with increasing ion fluence.