skip to main content

DOE PAGESDOE PAGES

Title: Island dynamics and anisotropy during vapor phase epitaxy of m-plane GaN

Using in situ grazing-incidence x-ray scattering, we have measured the diffuse scattering from islands that form during layer-by-layer growth of GaN by metal-organic vapor phase epitaxy on the (10$$\bar{1}$$0) m-plane surface. The diffuse scattering is extended in the (0001) in-plane direction in reciprocal space, indicating a strong anisotropy with islands elongated along [1$$\bar{2}$$10] and closely spaced along [0001]. This is confirmed by atomic force microscopy of a quenched sample. Islands were characterized as a function of growth rate F and temperature. Furthermore, the island spacing along [0001] observed during the growth of the first monolayer obeys a power-law dependence on growth rate F -n, with an exponent n=0.25±0.02. Our results are in agreement with recent kinetic Monte Carlo simulations, indicating that elongated islands result from the dominant anisotropy in step edge energy and not from surface diffusion anisotropy. The observed power-law exponent can be explained using a simple steady-state model, which gives n = 1/4.
Authors:
 [1] ; ORCiD logo [2] ;  [2] ;  [2] ;  [2] ;  [2] ;  [3] ; ORCiD logo [4]
  1. Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division; Univ. of Fribourg (Switzerland). Dept. of Physics, Fribourg Center for Nanomaterials
  2. Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division
  3. Munkholm Consulting, Mountain View, CA (United States)
  4. Northern Illinois Univ., DeKalb, IL (United States). Dept. of Physics
Publication Date:
Grant/Contract Number:
AC02-76SF00515; AC02-06CH11357
Type:
Publisher's Accepted Manuscript
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 111; Journal Issue: 23; Journal ID: ISSN 0003-6951
Publisher:
American Institute of Physics (AIP)
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1411116
Alternate Identifier(s):
OSTI ID: 1417298