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Title: Behavior of aluminum adsorption and incorporation at GaN(0001) surface: First-principles study

First-principles calculations are performed to study the energetics and atomic structures of aluminum adsorption and incorporation at clean and Ga-bilayer GaN(0001) surfaces. We find the favorable adsorption site changes from T4 to T1 as Al coverage increased to 1 monolayer on the clean GaN(0001) surface, and a two-dimensional hexagonal structure of Al overlayer appears. It is interesting the Al atoms both prefer to concentrate in one deeper Ga layer of clean and Ga-bilayer GaN(0001) surface, respectively, while different structures could be achieved in above surfaces. For the case of clean GaN(0001) surface, corresponding to N-rich and moderately Ga-rich conditions, a highly regular superlattice structure composed of wurtzite GaN and AlN becomes favorable. For the case of Ga-bilayer GaN(0001) surface, corresponding to extremely Ga-rich conditions, the Ga bilayer is found to be sustained stable in Al incorporating process, leading to an incommensurate structure directly. Furthermore, our calculations provide an explanation for the spontaneous formation of ordered structure and incommensurate structure observed in growing AlGaN films. The calculated results are attractive for further development of growth techniques and excellent AlGaN/GaN heterostructure electronic devices.
Authors:
; ;  [1] ;  [2]
  1. Key Laboratory for Optoelectronics and Communication of Jiangxi Province, Jiangxi Science and Technology Normal University, Nanchang 330018 (China)
  2. Theoretical Condensed Matter Physics and Computational Materials Physics Laboratory, University of Chinese Academy of Sciences, Beijing 101408 (China)
Publication Date:
OSTI Identifier:
22258749
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 114; Journal Issue: 19; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ADSORPTION; ALUMINIUM; ALUMINIUM NITRIDES; ELECTRONIC EQUIPMENT; GALLIUM NITRIDES; LAYERS; SUPERLATTICES