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Article: Structural and defect characterization of GaAs and Al xGa 1-xAs grown at low temperature by molecular beam epitaxy

TitleStructural and defect characterization of GaAs and Al xGa 1-xAs grown at low temperature by molecular beam epitaxy
Authors
Issue Date1997
PublisherAmerican Institute of Physics. The Journal's web site is located at http://jap.aip.org/jap/staff.jsp
Citation
Journal Of Applied Physics, 1997, v. 81 n. 1, p. 190-198 How to Cite?
AbstractWe have investigated the structural and defect characteristics of GaAs and Al xGa 1-xAs grown at low substrate temperature (250°C) by molecular beam epitaxy. Using x-ray diffraction we have observed an increase in lattice parameter for all as-grown layers, with the Al xGa 1-xAs layers showing a smaller expansion than the GaAs layer. However, infrared absorbtion measurements revealed that the concentration of neutral arsenic antisite defect, [As Ga] 0, was not significantly affected by aluminum content (x), with only a small reduction for x=0.36. Positron beam studies showed that the low temperature layers had a higher concentration of vacancy-related defects (∼10 17 cm -3) than the semi-insulating substrate, with the Al xGa 1-xAs layers having the highest values. After annealing (600°C, 15 min) the lattice constants relaxed to those of conventionally grown material and [As Ga] 0 was reduced in all cases, with the smallest reduction occurring for the x=0.36 layer, indicating that the Al atoms strengthen the lattice against excess arsenic incorporation and hold the arsenic antisite atoms more strongly in position. X-ray photoelectron spectroscopy showed that arsenic diffused out of the surface region and was replaced by oxygen, possibly due to an insufficient overpressure of forming gas during the anneal. This oxygen penetration was greater for the GaAs layer than for the Al xGa 1-xAs layers. Extra Raman peaks at 200 and 257 cm -1 confirmed that the surface was very disordered. There was, nevertheless, a large increase (4%) in the positron S parameter in the bulk of the annealed layers, suggesting the formation of vacancy clusters, whereas in the surface region we find evidence that As Ga diffusion proceeded at a faster rate in the x=0.36 than the x=0.2, in agreement with the vacancy-enhanced As Ga diffusion model. © 1997 American Institute of Physics.
Persistent Identifierhttp://hdl.handle.net/10722/174641
ISSN
2015 Impact Factor: 2.101
2015 SCImago Journal Rankings: 0.603
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorFleischer, Sen_HK
dc.contributor.authorBeling, CDen_HK
dc.contributor.authorFung, Sen_HK
dc.contributor.authorNieveen, WRen_HK
dc.contributor.authorSquire, JEen_HK
dc.contributor.authorZheng, JQen_HK
dc.contributor.authorMissous, Men_HK
dc.date.accessioned2012-11-26T08:46:39Z-
dc.date.available2012-11-26T08:46:39Z-
dc.date.issued1997en_HK
dc.identifier.citationJournal Of Applied Physics, 1997, v. 81 n. 1, p. 190-198en_HK
dc.identifier.issn0021-8979en_HK
dc.identifier.urihttp://hdl.handle.net/10722/174641-
dc.description.abstractWe have investigated the structural and defect characteristics of GaAs and Al xGa 1-xAs grown at low substrate temperature (250°C) by molecular beam epitaxy. Using x-ray diffraction we have observed an increase in lattice parameter for all as-grown layers, with the Al xGa 1-xAs layers showing a smaller expansion than the GaAs layer. However, infrared absorbtion measurements revealed that the concentration of neutral arsenic antisite defect, [As Ga] 0, was not significantly affected by aluminum content (x), with only a small reduction for x=0.36. Positron beam studies showed that the low temperature layers had a higher concentration of vacancy-related defects (∼10 17 cm -3) than the semi-insulating substrate, with the Al xGa 1-xAs layers having the highest values. After annealing (600°C, 15 min) the lattice constants relaxed to those of conventionally grown material and [As Ga] 0 was reduced in all cases, with the smallest reduction occurring for the x=0.36 layer, indicating that the Al atoms strengthen the lattice against excess arsenic incorporation and hold the arsenic antisite atoms more strongly in position. X-ray photoelectron spectroscopy showed that arsenic diffused out of the surface region and was replaced by oxygen, possibly due to an insufficient overpressure of forming gas during the anneal. This oxygen penetration was greater for the GaAs layer than for the Al xGa 1-xAs layers. Extra Raman peaks at 200 and 257 cm -1 confirmed that the surface was very disordered. There was, nevertheless, a large increase (4%) in the positron S parameter in the bulk of the annealed layers, suggesting the formation of vacancy clusters, whereas in the surface region we find evidence that As Ga diffusion proceeded at a faster rate in the x=0.36 than the x=0.2, in agreement with the vacancy-enhanced As Ga diffusion model. © 1997 American Institute of Physics.en_HK
dc.languageengen_US
dc.publisherAmerican Institute of Physics. The Journal's web site is located at http://jap.aip.org/jap/staff.jspen_HK
dc.relation.ispartofJournal of Applied Physicsen_HK
dc.rightsJournal of Applied Physics. Copyright © American Institute of Physics.-
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License-
dc.titleStructural and defect characterization of GaAs and Al xGa 1-xAs grown at low temperature by molecular beam epitaxyen_HK
dc.typeArticleen_HK
dc.identifier.emailBeling, CD: cdbeling@hkucc.hku.hken_HK
dc.identifier.emailFung, S: sfung@hku.hken_HK
dc.identifier.authorityBeling, CD=rp00660en_HK
dc.identifier.authorityFung, S=rp00695en_HK
dc.description.naturepublished_or_final_versionen_US
dc.identifier.doi10.1063/1.364105-
dc.identifier.scopuseid_2-s2.0-0001451387en_HK
dc.identifier.hkuros21262-
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0001451387&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume81en_HK
dc.identifier.issue1en_HK
dc.identifier.spage190en_HK
dc.identifier.epage198en_HK
dc.identifier.isiWOS:A1997WA94700029-
dc.publisher.placeUnited Statesen_HK
dc.identifier.scopusauthoridFleischer, S=7103394445en_HK
dc.identifier.scopusauthoridBeling, CD=7005864180en_HK
dc.identifier.scopusauthoridFung, S=7201970040en_HK
dc.identifier.scopusauthoridNieveen, WR=6602585331en_HK
dc.identifier.scopusauthoridSquire, JE=7102094478en_HK
dc.identifier.scopusauthoridZheng, JQ=16199204700en_HK
dc.identifier.scopusauthoridMissous, M=7007147933en_HK

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