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High carrier lifetimes in epitaxial germanium-tin/Al(In)As heterostructures with variable tin composition

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dc.contributor.authorHudait, Mantu K.en
dc.contributor.authorJohnston, Steven W.en
dc.contributor.authorClavel, Michael B.en
dc.contributor.authorBhattacharya, Shuvodipen
dc.contributor.authorKarthikeyan, Senguntharen
dc.contributor.authorJoshi, Rutwiken
dc.date.accessioned2023-02-21T17:55:11Zen
dc.date.available2023-02-21T17:55:11Zen
dc.date.issued2022-06-23en
dc.date.updated2023-02-17T19:50:20Zen
dc.description.abstractGroup IV-based germanium-tin (Ge1−ySny) compositional materials have recently shown great promise for infrared detection, light emission and ultra-low power transistors. High carrier lifetimes are desirable for enhancing the detection limit and efficiency of photodetectors, low threshold current density in lasers, and low tunneling barrier height by lowering defects and dislocations at the heterointerface of a source and a channel. Here, carrier lifetimes in epitaxial germanium (Ge) and variable tin (Sn) compositional Ge1−ySny materials were experimentally determined on GaAs substrates using the contactless microwave photoconductive decay (μ-PCD) technique at an excitation wavelength of 1500 nm. Sharp (2 × 2) reflection high energy electron diffraction patterns and low surface roughness were observed from the surface of the Ge0.97Sn0.03 epilayer. X-ray rocking curves from Ge0.97Sn0.03 and Ge0.94Sn0.06 layers demonstrated the pseudomorphic and lattice-matched growth on AlAs and In0.12Al0.88As buffers, respectively, further substantiated by reciprocal space maps and abrupt heterointerfaces evident from the presence of Pendellösung oscillations. High effective carrier lifetimes of 150 ns to 450 ns were measured for Ge1−ySny epilayers as a function of Sn composition, surface roughness, growth temperature, and layer thickness. The observed increase in the carrier lifetime with an increasing Ge layer thickness and a reducing surface roughness, by incorporating Sn, were explained. The enhancement of the carrier lifetime with an increasing Sn concentration was achieved by controlling the defects with lattice-matched Ge0.94Sn0.06/In0.12Al0.88As heterointerfaces or the pseudomorphic growth of Ge0.94Sn0.06 on GaAs. Therefore, our monolithic integration of variable Sn alloy compositional Ge1−ySny materials with high carrier lifetimes opens avenues to realize electronic and optoelectronic devices.en
dc.description.versionSubmitted versionen
dc.format.extentPages 10530-10540en
dc.format.mimetypeapplication/pdfen
dc.identifier.doihttps://doi.org/10.1039/d2tc00830ken
dc.identifier.eissn2050-7534en
dc.identifier.issn2050-7526en
dc.identifier.issue29en
dc.identifier.orcidHudait, Mantu [0000-0002-9789-3081]en
dc.identifier.urihttp://hdl.handle.net/10919/113891en
dc.identifier.volume10en
dc.language.isoenen
dc.publisherRoyal Society of Chemistryen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.titleHigh carrier lifetimes in epitaxial germanium-tin/Al(In)As heterostructures with variable tin compositionen
dc.title.serialJournal of Materials Chemistry Cen
dc.typeArticleen
dc.type.dcmitypeTexten
dc.type.otherArticleen
pubs.organisational-group/Virginia Techen
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

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