Room temperature PL efficiency of InGaN/GaN quantum well structures with prelayers as a function of number of quantum wells

Christian, George M. and Hammersley, Simon and Davies, Matthew J. and Dawson, Philip and Kappers, Menno J. and Massabuau, Fabien C.-P. and Oliver, Rachel A. and Humphreys, Colin J. (2016) Room temperature PL efficiency of InGaN/GaN quantum well structures with prelayers as a function of number of quantum wells. Physica Status Solidi C, 13 (5-6). pp. 248-251. ISSN 1610-1642 (https://doi.org/10.1002/pssc.201510180)

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Abstract

We report on the effects of varying the number of quantum wells (QWs) in an InGaN/GaN multiple QW (MQW) structure containing a 23 nm thick In0.05Ga0.95N prelayer doped with Si. The calculated conduction and valence bands for the structures show an increasing total electric field across the QWs with increasing number of QWs. This is due to the reduced strength of the surface polarisation field, which opposes the built-in field across the QWs, as its range is increased over thicker samples. Low temperature photoluminescence (PL) measurements show a red shifted QW emission peak energy, which is attributed to the enhanced quantum confined Stark effect with increasing total field strength across the QWs. Low temperature PL time decay measurements and room temperature internal quantum efficiency (IQE) measurements show decreasing radiative recombination rates and decreasing IQE, respectively, with increasing number of QWs. These are attributed to the increased spatial separation of the electron and hole wavefunctions, consistent with the calculated band profiles. It is also shown that, for samples with fewer QWs, the reduction of the total field across the QWs makes the radiative recombination rate sufficiently fast that it is competitive with the efficiency losses associated with the thermal escape of carriers.

  • Item type:Article
    ID code:79375
    Dates:
    Date
    Event
    31 May 2016
    Published
    27 January 2016
    Published Online
    15 December 2015
    Accepted
    Subjects:Science > Physics
    Department:Faculty of Science > Physics
    Depositing user: Pure Administrator
    Date deposited:28 Jan 2022 16:03
    Last modified:09 Apr 2024 03:00
    URI:https://strathprints.strath.ac.uk/id/eprint/79375
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