Volume 9, Issue 3-4 pp. 727-729
ICNS-9 – Contributed Article

Effect of GaN cap thickness on carrier dynamics in InGaN quantum wells

O. Kopylov

Corresponding Author

O. Kopylov

DTU Fotonik, Technical University of Denmark, Ørsteds Plads, 2800 Kgs Lyngby, Denmark

DTU Fotonik, Technical University of Denmark, Ørsteds Plads, 2800 Kgs Lyngby, DenmarkSearch for more papers by this author
R. Shirazi

R. Shirazi

DTU Fotonik, Technical University of Denmark, Ørsteds Plads, 2800 Kgs Lyngby, Denmark

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O. Svensk

O. Svensk

Department of Micro and Nanosciences, Aalto University, Tietotie 3, 02150 Espoo, Finland

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S. Suihkonen

S. Suihkonen

Department of Micro and Nanosciences, Aalto University, Tietotie 3, 02150 Espoo, Finland

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S. Sintonen

S. Sintonen

Department of Micro and Nanosciences, Aalto University, Tietotie 3, 02150 Espoo, Finland

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M. Sopanen

M. Sopanen

Department of Micro and Nanosciences, Aalto University, Tietotie 3, 02150 Espoo, Finland

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B. E. Kardynał

B. E. Kardynał

DTU Fotonik, Technical University of Denmark, Ørsteds Plads, 2800 Kgs Lyngby, Denmark

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First published: 21 November 2011
Citations: 2

Abstract

We have studied optical properties of single In0.1Ga0.9N quantum wells with GaN barriers in close proximity to the wafer surface (<10 nm). We have found that at room temperature a balance of radiative, non-radiative recombination and complex surface states effects results in an optimum cap thickness of 3nm for achieving highest brightness emitters. At low temperature, we observe a behaviour that suggests that some surface states act as trapping centres for carriers rather than as a non-radiative recombination channel. Temperature dependence of the photoluminescence decay curves shows that carrier lifetimes in all the wafers increase at lower temperatures and reach similar maximum value. Main features of the evolution of lifetimes with temperature can be explained satisfactory by a combination of radiative, non-radiative recombination and above mentioned twofold surface effects. Detailed picture of the carrier dynamics is however complex and needs to include the modification of the electrostatic potential in the quantum wells positioned in the surface depletion regions (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

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