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Optical Properties of Germanium Doped Cubic GaN

  • Donat J. As (a1), Michael Deppe (a1), Jürgen Gerlach (a2) and Dirk Reuter (a1)


We report on recent doping experiments of cubic GaN epilayers by Ge and investigate in detail the optical properties by photoluminescence spectroscopy. Plasma-assisted molecular beam epitaxy was used to deposit Ge-doped cubic GaN layers with nominal thicknesses of 600 nm on 3C-SiC(001)/Si(001) substrates. The Ge doping level could be varied by around six orders of magnitude by changing the Ge effusion cell temperature. A maximum free carrier concentration of 3.7×1020 cm-3 was measured in the GaN layers via Hall-effect at room temperature. Low temperature photoluminescence (PL) showed a clear shift of the donor-acceptor emission to higher energies with increasing Ge-doping. Above a Ge concentration of ∼ 2x1018cm-3 the near band edge lines merge to one broad band. From temperature dependent measurements of the observed excitonic and donor-acceptor transitions a donor-energy of ∼ 36 meV could be estimated for Ge.


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Optical Properties of Germanium Doped Cubic GaN

  • Donat J. As (a1), Michael Deppe (a1), Jürgen Gerlach (a2) and Dirk Reuter (a1)


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