Temperature and Doping-Dependent Interplay between Direct and Indirect Optical Response in Buffer-Mediated Epitaxial Germanium

dc.contributor.authorHudait, Mantu K.en
dc.contributor.authorMeeker, Michaelen
dc.contributor.authorLiu, Jheng-Sinen
dc.contributor.authorClavel, Michaelen
dc.contributor.authorBhattacharya, Shuvodipen
dc.contributor.authorKhodaparast, Gitien
dc.date.accessioned2023-02-17T20:32:07Zen
dc.date.available2023-02-17T20:32:07Zen
dc.date.issued2022-09-01en
dc.date.updated2023-02-17T19:27:20Zen
dc.description.abstractThe structural and optical properties of buffer mediated epitaxial germanium (Ge) layer were investigated and compared with bulk n-type and p-type Ge substrates. An interconnected dual-chamber molecular beam epitaxy (MBE) system was used to grow a 280 nm thin Ge epilayer on (100)GaAs substrate with an intermediate AlAs buffer layer. The lattice-matched, abrupt Ge/AlAs heterointerface was analyzed using cross-sectional transmission electron microscopic analysis, and no elemental interdiffusion was detected via secondary ion mass spectrometry. A strong direct gap transition, compared to the indirect gap transition, and a series of phonon-assisted transitions was observed by photoluminescence (PL) spectroscopy. In addition, the intensity of the direct gap recombination decreases with decreasing PL measurement temperatures, which was ascribed to the reduced density of Γ-valley electrons available for recombination at lower temperature. Furthermore, the intensity ratio between the direct and indirect optical transition drastically decreases with decreasing temperature in both n-type epitaxial and p-type bulk Ge. An empirical relation in both direct and indirect peak position with temperature was established. The observed strong luminescence in 280 nm thick epitaxial Ge at room temperature is vital for Ge-based photonic devices. In addition, the quality of the epitaxial Ge layer grown via MBE is on par with bulk Ge substrates.en
dc.description.versionSubmitted versionen
dc.format.mimetypeapplication/pdfen
dc.identifier112633 (Article number)en
dc.identifier.doihttps://doi.org/10.1016/j.optmat.2022.112633en
dc.identifier.issn0925-3467en
dc.identifier.orcidHudait, Mantu [0000-0002-9789-3081]en
dc.identifier.orcidKhodaparast, Giti [0000-0002-1597-6538]en
dc.identifier.urihttp://hdl.handle.net/10919/113861en
dc.identifier.volume131en
dc.language.isoenen
dc.publisherElsevieren
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.titleTemperature and Doping-Dependent Interplay between Direct and Indirect Optical Response in Buffer-Mediated Epitaxial Germaniumen
dc.title.serialOptical Materialsen
dc.typeArticleen
dc.type.dcmitypeTexten
dc.type.otherArticleen
pubs.organisational-group/Virginia Techen
pubs.organisational-group/Virginia Tech/Scienceen
pubs.organisational-group/Virginia Tech/Science/Physicsen
pubs.organisational-group/Virginia Tech/Engineeringen
pubs.organisational-group/Virginia Tech/Engineering/Electrical and Computer Engineeringen
pubs.organisational-group/Virginia Tech/All T&R Facultyen
pubs.organisational-group/Virginia Tech/Engineering/COE T&R Facultyen
pubs.organisational-group/Virginia Tech/Science/COS T&R Facultyen

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