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Title: Effect of annealing on the nonequilibrium carrier lifetime in GaAs grown at low temperatures

GaAs samples grown by molecular-beam epitaxy at low (230 Degree-Sign C) temperatures are investigated. One of the samples is subjected to aftergrowth annealing at 600 Degree-Sign C. Using an unconventional pump-probe scheme for measuring the dynamic variation in the light refractive index, the nonequilibrium charge-carrier lifetime (275 {+-} 30 fs before annealing) is determined. Such a short carrier lifetime in the unannealed material is due to the high concentration of point defects, mainly As{sub Ga} antisite defects. According to X-ray diffraction and steady-state optical absorption data, the As{sub Ga} concentration in the samples is 3 Multiplication-Sign 10{sup 19} cm{sup -3}, which corresponds to an arsenic excess of 0.26 at %. Upon annealing at 600 Degree-Sign C, the superstoichiometric As defects self-organize and form As nanoinclusions in the GaAs crystal matrix. It is shown that in this case the nonequilibrium charge-carrier lifetime increases to 452 {+-} 5 fs. This lifetime is apparently ensured by the capture of non-equilibrium charge carriers at metal As nanoinclusions.
Authors:
; ;  [1] ; ;  [2]
  1. St. Petersburg State University, Staryi Petergof (Russian Federation)
  2. Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)
Publication Date:
OSTI Identifier:
22210574
Resource Type:
Journal Article
Resource Relation:
Journal Name: Semiconductors; Journal Volume: 47; Journal Issue: 8; Other Information: Copyright (c) 2013 Pleiades Publishing, Ltd.; http://www.springer-ny.com; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ABSORPTION; ANNEALING; ARSENIC; CARRIER LIFETIME; CHARGE CARRIERS; CRYSTALS; GALLIUM ARSENIDES; MOLECULAR BEAM EPITAXY; POINT DEFECTS; REFRACTIVE INDEX; X-RAY DIFFRACTION