Scanning probe investigation of surface charge and surface potential of GaN-based heterostructures

Authors

B. J. Rodriguez, North Carolina State University, RaleighFollow
W.-C. Yang, North Carolina State University, Raleigh
R. J. Nemanich, North Carolina State University, Raleigh
Alexei Gruverman, University of Nebraska-LincolnFollow

Date of this Version

March 2005

Comments

Published in Appl. Phys. Lett. 86, 112115 (2005). Copyright © 2005 American Institute of Physics. Used by permission.

Abstract

Scanning Kelvin probe microscopy (SKPM( and electrostatic force microscopy (EFM) have been employed to measure the surface potentials and the surface charge densities of the Ga- and the N-face of a GaN lateral polarity heterostructure (LPH). The surface was subjected to an HCl surface treatment to address the role of adsorbed charge on polarization screening. It has been found that while the Ga-face surface appears to be unaffected by the surface treatment, the N-face surface exhibited an increase in adsorbed screening charge density (1.6±0.5x10¹⁰ cm−^-2), and a reduction of 0.3±0.1 V in the surface potential difference between the N- and Ga-face surfaces.