Precise determination of surface band bending in Ga-polar n-GaN films by angular dependent X-Ray photoemission spectroscopy.

ABSTRACT: We present a systematic study of surface band bending in Ga-polar n-GaN with different Si doping concentrations by angular dependent X-ray photoelectron spectroscopy (ADXPS). The binding energies of Ga 3d and N 1 s core levels in n-GaN films increase with increasing the emission angle, i. e., the probing depth, suggesting an upward surface band bending. By fitting the Ga 3d core level spectra at different emission angles and considering the integrated effect of electrostatic potential, the core level energy at the topmost surface layer is well corrected, therefore, the surface band bending is precisely evaluated. For moderately doped GaN, the electrostatic potential can be reflected by the simply linear potential approximation. However, for highly doped GaN samples, in which the photoelect

SUBMITTER: Zhao Y 

PROVIDER: S-EPMC6861320 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature