Dresden 2017 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 64: Poster: Photovoltaics and Optics

HL 64.9: Poster

Wednesday, March 22, 2017, 15:00–19:00, P1C

MgZnO/ZnO quantum wells with distinct quantum-confined stark effect grown on a highly conductive ZnO:Al back contact layer — •Max Kneiß, Gabriele Benndorf, Holger von Wenckstern, and Marius Grundmann — Universität Leipzig, Institut für Experimentelle Physik II, Leipzig, Germany

Since stable p-type doping in ZnO has not been achieved until now [1], methods beyond traditional doping strategies have to be employed to realize high hole densities. One approach is the separation of photo-excited electrons and holes in the internal electric field of polar MgZnO/ZnO quantum wells (QWs) [2]. The effectiveness of the separation can be estimated by the gound state recombination energy and decay time of the QW emission and the internal field. To directly determine the latter, external field-dependent photoluminescence (PL) measurements can be used where a highly conductive back contact layer is needed. We have grown MgZnO/ZnO QWs on a degenerately doped ZnO:Al layer via pulsed laser deposition. Low temperature PL spectra showed a blue-shift of the QW emission with increasing excitation density indicating a quantum-confined stark effect resulting from the internal field. We modeled the temporal dynamics of the QW emission and determined ground state recombination energies and decay times of the QW excitons in dependence on the well width for symmetric QWs as well as the Mg-content in the upper MgZnO layer for QWs with asymmetric barriers. We further verified the internal field by field-dependent cw-PL spectroscopy. [1] Fan et al., Prog. Mater. Sci. 58, 874 (2013) , [2] Stölzel et al., Phys. Rev. B 88, 045315 (2013)