Self-trapping and ordering of heavy holes in the wide band-gap semiconductor β-Ga2O3

Scanning tunneling microscopy (STM) has been utilized for imaging and manipulation of self-trapped holes on the surface of the wide band-gap semiconductor beta-Ga2O3. A positively charged surface layer comprised of localized holes with 10(13) cm(-2) density has been observed for n-doped samples. We show that the surface layer can be populated by hole pumping from the STM tip. A transition between the glassy phase and ordered striped phase of self-trapped holes has also been observed. Our analysis indicates that the saturated two-dimensional density of self-trapped holes may be determined by balance of self-trapping and Coulomb repulsion energies.