Characterisation of InGaN by photoconductive atomic force microscopy

Weatherley, Thomas F. K. and Massabuau, Fabien C.-P. and Kappers, Menno J. and Oliver, Rachel A. (2018) Characterisation of InGaN by photoconductive atomic force microscopy. Materials, 11 (10). 1794. ISSN 1996-1944 (https://doi.org/10.3390/ma11101794)

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Abstract

Nanoscale structure has a large effect on the optoelectronic properties of InGaN, a material vital for energy saving technologies such as light emitting diodes. Photoconductive atomic force microscopy (PC-AFM) provides a new way to investigate this effect. In this study, PC-AFM was used to characterise four thick (∼130 nm) In x Ga 1−x N films with x = 5%, 9%, 12%, and 15%. Lower photocurrent was observed on elevated ridges around defects (such as V-pits) in the films with x≤12 %. Current-voltage curve analysis using the PC-AFM setup showed that this was due to a higher turn-on voltage on these ridges compared to surrounding material. To further understand this phenomenon, V-pit cross sections from the 9% and 15% films were characterised using transmission electron microscopy in combination with energy dispersive X-ray spectroscopy. This identified a subsurface indium-deficient region surrounding the V-pit in the lower indium content film, which was not present in the 15% sample. Although this cannot directly explain the impact of ridges on turn-on voltage, it is likely to be related. Overall, the data presented here demonstrate the potential of PC-AFM in the field of III-nitride semiconductors.

  • Item type:Article
    ID code:79475
    Dates:
    Date
    Event
    21 September 2018
    Published
    3 September 2018
    Accepted
    Notes:This article belongs to the Special Issue III-Nitrides Semiconductor Research in the UK and Ireland
    Subjects:Technology > Mining engineering. Metallurgy
    Department:Faculty of Science > Physics
    Depositing user: Pure Administrator
    Date deposited:04 Feb 2022 11:19
    Last modified:25 Apr 2024 01:25
    URI:https://strathprints.strath.ac.uk/id/eprint/79475
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