Investigation of {111} Hydrogen Platelet Defects in Proton Bombarded GaAs using Cs-corrected STEM

Abstract

Probe-Cs-corrected high angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) is used to image loop-like defects on {111} planes in high-dose proton bombarded (10 17 H+ cm-2) n-type GaAs. The typical {111} loop-like defect present at the peak of the H+ projected range in the 300 keV proton bombarded GaAs was found to consist of a single {111} GaAs layer with adjacent areas of lower crystal density which are suggested to be small hydrogen bubbles formed by H2 molecules trapped at tetrahedral sites adjacent to the {111} plane of the interstitial loop. It has been suggested that in GaAs, H diffuses in atomic form until trapped at a defect with the subsequent formation of a H 2 molecule which is not mobile. This paper presents the first atomic resolution images of hydrogen platelet defects on {111} planes of high dose proton bombarded GaAs.