Accurate determination of polarization fields in (0 0 0 1) c-plane InAlN/GaN heterostructures with capacitance-voltage measurements

N. Susilo1, G.G. Roumeliotis1,2, M. Narodovitch3, B. Witzigmann4, M. Rychetsky1, S. Neugebauer5, M. Guttmann1, J. Enslin1, A. Dadgar5, T. Niermann3, T. Wernicke1, A. Strittmatter5, M. Lehmann3, D.N. Papadimitriou1,2, and M. Kneissl1,6

Published in:

J. Phys. D: Appl. Phys., vol. 51, no. 48, pp. 485103 (2018).

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In this paper the internal electric fields of nearly lattice matched InAlN/GaN heterostructures were determined. Pin-diodes containing InAlN/GaN heterostructures grown on (0001) sapphire substrates by metalorganic vapour phase epitaxy were fabricated by standard lithography and metallization techniques. To determine the polarization fields in the InAlN quantum wells capacitance-voltage-measurements were performed on the pin-diodes. To reduce the measurement error, the heterostructure thicknesses were accurately determined by transmission electron microscopy. Large polarization fields, which correspond mainly to the spontaneous polarizations, for In0.15Al0.85N (5.9 ± 0.8 MV cm-1), In0.18Al0.82N (5.4 ± 0.9 MV cm-1) and In0.21Al0.79N (5.1 ± 0.8 MV cm-1) quantum wells were observed. The results of the internal field strength and field direction are in excellent agreement with values predicted by theory and a CVM-based coupled Poisson/carrier transport simulation approach.

1 Institute of Solid State Physics, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
2 National Technical University of Athens, Heroon Polytechniou 9, 15780 Athens, Greece
3 Institute of Optics and Atomic Physics, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
4 Universität Kassel, Computational Electronics and Photonics Group and CINSaT, Kassel, Germany
5 Institute of Physics, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany
6 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, 12489 Berlin, Germany