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Article: Positron beam study of low-temperature-grown GaAs with aluminum delta layers

TitlePositron beam study of low-temperature-grown GaAs with aluminum delta layers
Authors
Issue Date1999
PublisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/apsusc
Citation
Applied Surface Science, 1999, v. 149 n. 1, p. 159-164 How to Cite?
AbstractWe report on the use of a slow-positron beam to examine aluminum delta layers in GaAs grown at low substrate temperature (250 °C) by molecular beam epitaxy (LTMBE). It is now established that LTMBE-GaAs contains an excess of arsenic which causes an increase in the lattice parameter. After annealing, this arsenic is redistributed and forms precipitates resulting in the relaxation of the lattice. Previous positron beam studies have shown that the as-grown material has a large concentration of gallium vacancies, and after annealing the S-parameter increases above the as-grown value indicating that vacancy clusters have formed. A region depleted of arsenic precipitates has been shown to form near to aluminum delta layers, and this work is the first to study the vacancy distribution associated with this depletion region. We observe that the as-grown material has a peak value of the normalized S-parameter that is approximately 3.5% higher than the substrate, which is much larger than that for a single layer LT-GaAs structure (0.8-1.5%). After annealing in the range 600-800 °C the S-parameter collapses down to the substrate value, which again is opposite to the LT-GaAs case and indicates that few precipitates have formed. We correlate these findings with SIMS and TEM data and propose a mechanism involving compositional disordering due to the aluminum layers.
Persistent Identifierhttp://hdl.handle.net/10722/80595
ISSN
2015 Impact Factor: 3.15
2015 SCImago Journal Rankings: 0.930
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorFleischer, Sen_HK
dc.contributor.authorHu, YFen_HK
dc.contributor.authorBeling, CDen_HK
dc.contributor.authorFung, Sen_HK
dc.contributor.authorSmith, TLen_HK
dc.contributor.authorMoulding, KMen_HK
dc.contributor.authorWeng, HMen_HK
dc.contributor.authorMissous, Men_HK
dc.date.accessioned2010-09-06T08:08:10Z-
dc.date.available2010-09-06T08:08:10Z-
dc.date.issued1999en_HK
dc.identifier.citationApplied Surface Science, 1999, v. 149 n. 1, p. 159-164en_HK
dc.identifier.issn0169-4332en_HK
dc.identifier.urihttp://hdl.handle.net/10722/80595-
dc.description.abstractWe report on the use of a slow-positron beam to examine aluminum delta layers in GaAs grown at low substrate temperature (250 °C) by molecular beam epitaxy (LTMBE). It is now established that LTMBE-GaAs contains an excess of arsenic which causes an increase in the lattice parameter. After annealing, this arsenic is redistributed and forms precipitates resulting in the relaxation of the lattice. Previous positron beam studies have shown that the as-grown material has a large concentration of gallium vacancies, and after annealing the S-parameter increases above the as-grown value indicating that vacancy clusters have formed. A region depleted of arsenic precipitates has been shown to form near to aluminum delta layers, and this work is the first to study the vacancy distribution associated with this depletion region. We observe that the as-grown material has a peak value of the normalized S-parameter that is approximately 3.5% higher than the substrate, which is much larger than that for a single layer LT-GaAs structure (0.8-1.5%). After annealing in the range 600-800 °C the S-parameter collapses down to the substrate value, which again is opposite to the LT-GaAs case and indicates that few precipitates have formed. We correlate these findings with SIMS and TEM data and propose a mechanism involving compositional disordering due to the aluminum layers.en_HK
dc.languageengen_HK
dc.publisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/apsuscen_HK
dc.relation.ispartofApplied Surface Scienceen_HK
dc.rightsApplied Surface Science. Copyright © Elsevier BV.en_HK
dc.titlePositron beam study of low-temperature-grown GaAs with aluminum delta layersen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0169-4332&volume=149&spage=159&epage=164&date=1999&atitle=Positron+Beam+Study+of+Low-Temperature-Grown+GaAs+with+Aluminium+Delta+Layersen_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.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1016/S0169-4332(99)00193-2en_HK
dc.identifier.scopuseid_2-s2.0-0032661218en_HK
dc.identifier.hkuros47336en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0032661218&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume149en_HK
dc.identifier.issue1en_HK
dc.identifier.spage159en_HK
dc.identifier.epage164en_HK
dc.identifier.isiWOS:000082445300032-
dc.publisher.placeNetherlandsen_HK
dc.identifier.scopusauthoridFleischer, S=7103394445en_HK
dc.identifier.scopusauthoridHu, YF=7407119615en_HK
dc.identifier.scopusauthoridBeling, CD=7005864180en_HK
dc.identifier.scopusauthoridFung, S=7201970040en_HK
dc.identifier.scopusauthoridSmith, TL=7405497420en_HK
dc.identifier.scopusauthoridMoulding, KM=6701466356en_HK
dc.identifier.scopusauthoridWeng, HM=7102468725en_HK
dc.identifier.scopusauthoridMissous, M=7007147933en_HK

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