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Title: Influence of grain size and surface condition on minority-carrier lifetime in undoped n-BaSi{sub 2} on Si(111)

We have fabricated approximately 0.5-μm-thick undoped n-BaSi{sub 2} epitaxial films with various average grain areas ranging from 2.6 to 23.3 μm{sup 2} on Si(111) by molecular beam epitaxy, and investigated their minority-carrier lifetime properties by the microwave-detected photoconductivity decay method at room temperature. The measured excess-carrier decay curves were divided into three parts in terms of decay rate. We characterized the BaSi{sub 2} films using the decay time of the second decay mode, τ{sub SRH}, caused by Shockley-Read-Hall recombination without the carrier trapping effect, as a measure of the minority-carrier properties in the BaSi{sub 2} films. The measured τ{sub SRH} was grouped into two, independently of the average grain area of BaSi{sub 2}. BaSi{sub 2} films with cloudy surfaces or capped intentionally with a 3 nm Ba or Si layer, showed large τ{sub SRH} (ca. 8 μs), whereas those with mirror surfaces much smaller τ{sub SRH} (ca. 0.4 μs). X-ray photoelectron spectroscopy measurements were performed to discuss the surface region of the BaSi{sub 2} films.
Authors:
; ; ; ;  [1] ;  [2] ;  [2] ;  [3] ;  [1] ;  [3]
  1. Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan)
  2. Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan)
  3. (Japan)
Publication Date:
OSTI Identifier:
22304407
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 19; 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; BARIUM SILICATES; CARRIER LIFETIME; FILMS; GRAIN SIZE; LAYERS; MICROWAVE RADIATION; MOLECULAR BEAM EPITAXY; N-TYPE CONDUCTORS; PHOTOCONDUCTIVITY; RECOMBINATION; SURFACES; TEMPERATURE RANGE 0273-0400 K; TRAPPING; X-RAY PHOTOELECTRON SPECTROSCOPY