Exciton confinement in homo- and heteroepitaxial ZnO/Zn{sub 1-x}Mg{sub x}O quantum wells with x < 0.1

Journal Article · Tue Nov 01 04:00:00 EDT 2011 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3658020· OSTI ID:22038755

Laumer, Bernhard ^[1]; Wassner, Thomas A; Schuster, Fabian; Stutzmann, Martin ^[1]; Schoermann, Joerg; Eickhoff, Martin ^[2]; Rohnke, Marcus ^[3]; Chernikov, Alexej; Bornwasser, Verena; Koch, Martin; Chatterjee, Sangam ^[4]

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1. Walter Schottky Institut, Technische Universitaet Muenchen, Am Coulombwall 4, 85748 Garching (Germany)
2. I. Physikalisches Institut, Justus-Liebig-Universitaet Giessen, Heinrich-Buff-Ring 16, 35392 Giessen (Germany)
3. Institut fuer Physikalische Chemie, Justus-Liebig-Universitaet Giessen, Heinrich-Buff-Ring 58, 35392 Giessen (Germany)
4. Faculty of Physics and Materials Science Center, Philipps-Universitaet Marburg, Renthof 5, 35032 Marburg (Germany)

ZnO/Zn{sub 1-x}Mg{sub x}O single quantum well (SQW) structures with well widths d{sub W} between 1.1 nm and 10.4 nm were grown by plasma-assisted molecular beam epitaxy both heteroepitaxially on c-plane sapphire and homoepitaxially on (0001)-oriented bulk ZnO. A significantly reduced Mg incorporation in the top barrier related to the generation of stacking faults is observed for heteroepitaxial samples. Exciton localization is observed for both types of samples, while an enhancement of the exciton binding energy compared to bulk ZnO is only found for homoepitaxial SQWs for 2 nm {<=} d{sub W} {<=} 4 nm. Consistently, for homoepitaxial samples, the carrier dynamics are mainly governed by radiative recombination and carrier cooling processes at temperatures below 170 K, whereas thermally activated non-radiative recombination dominates in heteroepitaxial samples. The effects of polarization-induced electric fields are concealed for Mg concentrations x < 0.1 due to the reduction of the exciton binding energy, the screening by residual carriers as well as the asymmetric barrier structure in heteroepitaxial wells.

• OSTI ID: 22038755
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 9 Vol. 110; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
77 NANOSCIENCE AND NANOTECHNOLOGY
BINDING ENERGY
CRYSTAL GROWTH
ELECTRIC FIELDS
EXCITONS
HOLES
INTERFACES
MAGNESIUM OXIDES
MOLECULAR BEAM EPITAXY
PLASMA
POLARIZATION
QUANTUM WELLS
RECOMBINATION
SAPPHIRE
SEMICONDUCTOR MATERIALS
STACKING FAULTS
ZINC OXIDES