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Article: Semi-insulating GaAs: A possible substrate for a field-assisted positron moderator

TitleSemi-insulating GaAs: A possible substrate for a field-assisted positron moderator
Authors
Keywords72.20.Ht
78.70.Bj
79.90
Issue Date1994
PublisherSpringer Verlag. The Journal's web site is located at http://link.springer.de/link/service/journals/00339/index.htm
Citation
Applied Physics A Solids And Surfaces, 1994, v. 59 n. 3, p. 259-273 How to Cite?
AbstractPositron lifetime spectroscopy measurements have been carried out for semi-insulating GaAs with applied electric fields in the samples directed towards, and away from the positron injecting contact. The lifetime spectra have been decomposed into two components, the longer of which (≈400 ps) is characteristic of open volume defects at the metal-semiconductor interface through which positrons are injected. The interesting feature of these experiments is the large increase in the intensity of this interface component as the field is directed towards the contact. We show that this increase is caused by a significant fraction of implanted positrons drifting under the influence of a strong electric field produced by a layer of space-charge formed adjacent to the positron injecting contact. The general trend of the intensity variation is well explained by the proposed model. Experiments involving the application of an ac bias to the samples strengthen the suggestion that the space charge region is largely formed from ionized EL2 donors. The results of the present work indicate that semi-insulating GaAs possesses properties that make it a suitable material for the fabrication of a high efficiency (≈10%) room-temperature field-assisted positron moderator. The extraction of positrons from the GaAs substrate into the vacuum through a thin metalization is discussed based upon available positron affinities for the GaAs and various elemental metals. These data suggest that a few monolayers of a strongly electronegative metal such as Au or Pd may allow vacuum emission through quantum tunneling. © 1994 Springer-Verlag.
Persistent Identifierhttp://hdl.handle.net/10722/80922
ISSN
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorShan, YYen_HK
dc.contributor.authorAu, HLen_HK
dc.contributor.authorLing, CCen_HK
dc.contributor.authorLee, TCen_HK
dc.contributor.authorPanda, BKen_HK
dc.contributor.authorFung, Sen_HK
dc.contributor.authorBeling, CDen_HK
dc.contributor.authorWang, YYen_HK
dc.contributor.authorWeng, HMen_HK
dc.date.accessioned2010-09-06T08:11:46Z-
dc.date.available2010-09-06T08:11:46Z-
dc.date.issued1994en_HK
dc.identifier.citationApplied Physics A Solids And Surfaces, 1994, v. 59 n. 3, p. 259-273en_HK
dc.identifier.issn0721-7250en_HK
dc.identifier.urihttp://hdl.handle.net/10722/80922-
dc.description.abstractPositron lifetime spectroscopy measurements have been carried out for semi-insulating GaAs with applied electric fields in the samples directed towards, and away from the positron injecting contact. The lifetime spectra have been decomposed into two components, the longer of which (≈400 ps) is characteristic of open volume defects at the metal-semiconductor interface through which positrons are injected. The interesting feature of these experiments is the large increase in the intensity of this interface component as the field is directed towards the contact. We show that this increase is caused by a significant fraction of implanted positrons drifting under the influence of a strong electric field produced by a layer of space-charge formed adjacent to the positron injecting contact. The general trend of the intensity variation is well explained by the proposed model. Experiments involving the application of an ac bias to the samples strengthen the suggestion that the space charge region is largely formed from ionized EL2 donors. The results of the present work indicate that semi-insulating GaAs possesses properties that make it a suitable material for the fabrication of a high efficiency (≈10%) room-temperature field-assisted positron moderator. The extraction of positrons from the GaAs substrate into the vacuum through a thin metalization is discussed based upon available positron affinities for the GaAs and various elemental metals. These data suggest that a few monolayers of a strongly electronegative metal such as Au or Pd may allow vacuum emission through quantum tunneling. © 1994 Springer-Verlag.en_HK
dc.languageengen_HK
dc.publisherSpringer Verlag. The Journal's web site is located at http://link.springer.de/link/service/journals/00339/index.htmen_HK
dc.relation.ispartofApplied Physics A Solids and Surfacesen_HK
dc.subject72.20.Hten_HK
dc.subject78.70.Bjen_HK
dc.subject79.90en_HK
dc.titleSemi-insulating GaAs: A possible substrate for a field-assisted positron moderatoren_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0947-8396&volume=59&spage=259&epage=273&date=1994&atitle=Semi-insulating+GaAs:+a+possible+substrate+for+a+field-assisted+positron+moderatoren_HK
dc.identifier.emailLing, CC: ccling@hkucc.hku.hken_HK
dc.identifier.emailFung, S: sfung@hku.hken_HK
dc.identifier.emailBeling, CD: cdbeling@hkucc.hku.hken_HK
dc.identifier.authorityLing, CC=rp00747en_HK
dc.identifier.authorityFung, S=rp00695en_HK
dc.identifier.authorityBeling, CD=rp00660en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1007/BF00348229en_HK
dc.identifier.scopuseid_2-s2.0-0028514043en_HK
dc.identifier.hkuros3336en_HK
dc.identifier.volume59en_HK
dc.identifier.issue3en_HK
dc.identifier.spage259en_HK
dc.identifier.epage273en_HK
dc.identifier.isiWOS:A1994PE57900006-
dc.identifier.scopusauthoridShan, YY=7203036700en_HK
dc.identifier.scopusauthoridAu, HL=7004152230en_HK
dc.identifier.scopusauthoridLing, CC=13310239300en_HK
dc.identifier.scopusauthoridLee, TC=36347141200en_HK
dc.identifier.scopusauthoridPanda, BK=22963418500en_HK
dc.identifier.scopusauthoridFung, S=7201970040en_HK
dc.identifier.scopusauthoridBeling, CD=7005864180en_HK
dc.identifier.scopusauthoridWang, YY=7601511509en_HK
dc.identifier.scopusauthoridWeng, HM=7102468725en_HK

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