Disentangling nonradiative recombination processes in Ge micro-crystals on Si substrates

Journal Article · Mon Jun 27 04:00:00 EDT 2016 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4955020· OSTI ID:22590656

Pezzoli, Fabio; Giorgioni, Anna; Gatti, Eleonora; Grilli, Emanuele; Bonera, Emiliano; Miglio, Leo ^[1]; Gallacher, Kevin; Millar, Ross W.; Paul, Douglas J. ^[2]; Isa, Fabio ^[3]; Biagioni, Paolo ^[4]; Isella, Giovanni ^[3]

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1. LNESS and Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca, via Cozzi 55, I-20125 Milano (Italy)
2. School of Engineering, University of Glasgow, Rankine Building, Oakfield Avenue, Glasgow G12 8LT (United Kingdom)
3. LNESS, Dipartimento di Fisica del Politecnico di Milano and IFN-CNR, Polo Territoriale di Como, Via Anzani 42, I-22100 Como (Italy)
4. LNESS, Dipartimento di Fisica del Politecnico di Milano and IFN-CNR, Piazza Leonardo da Vinci 32, I-20133 Milano (Italy)

We address nonradiative recombination pathways by leveraging surface passivation and dislocation management in μm-scale arrays of Ge crystals grown on deeply patterned Si substrates. The time decay photoluminescence (PL) at cryogenic temperatures discloses carrier lifetimes approaching 45 ns in band-gap engineered Ge micro-crystals. This investigation provides compelling information about the competitive interplay between the radiative band-edge transitions and the trapping of carriers by dislocations and free surfaces. Furthermore, an in-depth analysis of the temperature dependence of the PL, combined with capacitance data and finite difference time domain modeling, demonstrates the effectiveness of GeO{sub 2} in passivating the surface of Ge and thus in enhancing the room temperature PL emission.

• OSTI ID: 22590656
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 26 Vol. 108; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CAPACITANCE
CARRIER LIFETIME
CRYSTALS
DISLOCATIONS
GERMANATES
GERMANIUM OXIDES
PASSIVATION
PHOTOLUMINESCENCE
RECOMBINATION
SIMULATION
SUBSTRATES
SURFACES
TEMPERATURE RANGE 0273-0400 K
TRAPPING