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Title: Materials properties and dislocation dynamics in InAsP compositionally graded buffers on InP substrates

The properties of InAs{sub x}P{sub 1−x} compositionally graded buffers grown by metal organic chemical vapor deposition are investigated. We report the effects of strain gradient (ε/thickness), growth temperature, and strain initiation sequence (gradual or abrupt strain introduction) on threading dislocation density, surface roughness, epi-layer relaxation, and tilt. We find that gradual introduction of strain causes increased dislocation densities (>10{sup 6}/cm{sup 2}) and tilt of the epi-layer (>0.1°). A method of abrupt strain initiation is proposed which can result in dislocation densities as low as 1.01 × 10{sup 5} cm{sup −2} for films graded from the InP lattice constant to InAs{sub 0.15}P{sub 0.85}. A model for a two-energy level dislocation nucleation system is proposed based on our results.
Authors:
; ;  [1]
  1. Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave. Cambridge, Massachusetts 02139 (United States)
Publication Date:
OSTI Identifier:
22273565
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 15; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CHEMICAL VAPOR DEPOSITION; DENSITY; DISLOCATIONS; ENERGY LEVELS; INDIUM ARSENIDES; INDIUM PHOSPHIDES; LATTICE PARAMETERS; LAYERS; ORGANOMETALLIC COMPOUNDS; STRAINS; SUBSTRATES; SURFACES; THIN FILMS