Structural and luminescence imaging and characterisation of semiconductors in the scanning electron microscope
Semicond. Sci. Technol., vol. 35, no. 05, Special Issue: Nitride Semiconductors, pp. 054001, DOI: 10.1088/1361-6641/ab75a5 (2020).
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The scanning electron microscopy techniques of electron backscatter diffraction (EBSD), electron channelling contrast imaging(ECCI) and cathodoluminescence (CL) hyperspectral imaging provide complementary information on the structural and luminescence properties of materials rapidly and non-destructively, with a spatial resolution of tens of nanometres. EBSD provides crystal orientation, crystal phase and strain analysis, whilst ECCI is used to determine the planar distribution of extended defects over a large area of a given sample. CL reveals the influence of crystal structure, composition and strain on intrinsic luminescence and/or reveals defect-related luminescence. Dark features are also observed in CL images where carrier recombination at defects is non-radiative. The combination of these techniques is a powerful approach to clarifying the role of crystallography and extended defects on a material’s light emission properties. Here we describe the EBSD, ECCI and CL techniques and illustrate their use for investigating the structural and light emitting properties of UV-emitting nitride semiconductor structures. We discuss our investigations of the type, density and distribution of defects in GaN, AlN and AlGaN thin films and also discuss the determination of the polarity of GaN nanowires.
1 Department of Physics, SUPA, University of Strathclyde, Glasgow, G4 0NG, United Kingdom
2 Tyndall National Institute, University College Cork, Cork, T12 R5CP, Ireland
3 Institut für Festkörperphysik, Technische Universität Berlin, 10623 Berlin, Germany
4 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, 12489 Berlin, Germany
5 Department of Electronic and Electrical Engineering, University of Bath, Bath, BA2 7AY, United Kingdom
6 Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, S1 3JD, United Kingdom
7 Academic Centre for Materials and Nanotechnology (ACMiN), AGH University of Science andTechnology, Krakow, Poland
SEM, EBSD, CL, ECCI, nitride, extended defects.