Dresden 2017 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 59: Nitrides: Preparation and Characterization II

HL 59.7: Vortrag

Mittwoch, 22. März 2017, 16:45–17:00, POT 251

Photoluminescence spectroscopy of Ge-doped cubic GaN — •Michael Deppe¹, Jürgen W. Gerlach², Dirk Reuter¹, and Donat J. As¹ — ¹Universität Paderborn, Department Physik, Warburger Straße 100, 33098 Paderborn — ²Leibniz-Institut für Oberflächenmodifizierung e.V., Permoserstraße 15, 04318 Leipzig

Recently, germanium was introduced as an alternative to silicon for n-type doping of cubic GaN. We demonstrated that free carrier concentrations up to 3.7 × 10²⁰ cm⁻³ can be obtained and the incorporation of Ge is in good agreement to the trend of the Ge vapour pressure curve in a doping range spanning several orders of magnitude [1]. In this contribution we report on the optical properties of Ge-doped cubic GaN determined by photoluminescence (PL) spectroscopy. Cubic GaN layers with nominal thicknesses of 600 nm were grown by plasma-assisted molecular beam epitaxy on 10 µm thick 3C-SiC(001)/Si(001) substrates. The Ge doping level was varied by about six order of magnitude by varying the Ge effusion cell temperature between 600 ^∘C and 1000 ^∘C. PL spectra were obtained for sample temperatures between 13 K and 300 K. Above a Ge concentration of approximately 2 × 10¹⁸ cm⁻³ the near band edge emission lines merge to a broad band. A donor ionization energy of about 36 meV was estimated.

[1] M. Deppe, J. W. Gerlach, D. Reuter, and D. J. As, Phys. Stat. Sol (b) (2016) (submitted)