The effect of AlN interlayer thicknesses on scattering processes in lattice-matched AlInN/GaN two-dimensional electron gas heterostructures

buir.contributor.authorÖzbay, Ekmel
buir.contributor.orcidÖzbay, Ekmel|0000-0003-2953-1828
dc.citation.epage063031-12en_US
dc.citation.spage063031-1en_US
dc.citation.volumeNumber11en_US
dc.contributor.authorTeke, A.en_US
dc.contributor.authorGökden, S.en_US
dc.contributor.authorTülek, R.en_US
dc.contributor.authorLeach, J.H.en_US
dc.contributor.authorFan, Q.en_US
dc.contributor.authorXie, J.en_US
dc.contributor.authorÖzgür, Ü.en_US
dc.contributor.authorMorkoç, H.en_US
dc.contributor.authorLisesivdin, S. B.en_US
dc.contributor.authorÖzbay, Ekmelen_US
dc.date.accessioned2016-02-08T10:03:55Z
dc.date.available2016-02-08T10:03:55Z
dc.date.issued2009en_US
dc.departmentDepartment of Electrical and Electronics Engineeringen_US
dc.departmentNanotechnology Research Center (NANOTAM)en_US
dc.departmentDepartment of Physicsen_US
dc.departmentInstitute of Materials Science and Nanotechnology (UNAM)en_US
dc.description.abstractThe scattering mechanisms governing the transport properties of high mobility AllnN/AlN/GaN two-dimensional electron gas (2DEG) heterostructures with various AIN spacer layer thicknesses from zero to 2 nm were presented. The major scattering processes including acoustic and optical phonons, ionized impurity, interface roughness, dislocation and alloy disorder were applied to the temperature-dependent mobility data. It was found that scattering due mainly to alloy disorder limits the electron mobility for samples having spacer layer thicknesses up to 0.3 nm. On the other hand, alloy scattering is greatly reduced as the AlN spacer layer thickness increases further, and hence the combination of acoustic, optical and interface roughness become operative with different degrees of effectiveness over different temperature ranges. The room-temperature electron mobility was observed to increase gradually as the AlN spacer layer increases. A peak electron mobility of 1630 cm2 V-1s -1 was realized for the sample consisting of a 1 nm AlN spacer layer. Then, the electron mobility decreased for the sample with 2 nm AlN. Moreover, the measured 2DEG densities were also compared with the theoretical predictions, which include both piezoelectric and spontaneous polarization components existing at AlN/GaN interfaces. The experimental sheet carrier densities for all AllnN/AlN/GaN HEMT structures were found to be in excellent agreement with the theoretical predictions when the parasitic (unintentional) GaN layer deposited between AlN and AllnN was taken into account. From these analyses, 1 nm AlN spacer layer thickness is found to be the optimum thickness required for high electron mobility and hence low sheet resistance once the sheet carrier density is increased to the theoretically expected value for the sample without unintentional GaN layer.en_US
dc.description.provenanceMade available in DSpace on 2016-02-08T10:03:55Z (GMT). No. of bitstreams: 1 bilkent-research-paper.pdf: 70227 bytes, checksum: 26e812c6f5156f83f0e77b261a471b5a (MD5) Previous issue date: 2009en
dc.identifier.doi10.1088/1367-2630/11/6/063031en_US
dc.identifier.issn1367-2630
dc.identifier.urihttp://hdl.handle.net/11693/22721
dc.language.isoEnglishen_US
dc.publisherInstitute of Physics Publishing Ltd.en_US
dc.relation.isversionofhttp://doi.org/10.1088/1367-2630/11/6/063031en_US
dc.source.titleNew Journal of Physicsen_US
dc.titleThe effect of AlN interlayer thicknesses on scattering processes in lattice-matched AlInN/GaN two-dimensional electron gas heterostructuresen_US
dc.typeArticleen_US

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