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HL: Fachverband Halbleiterphysik

HL 68: Nitrides: Preparation and characterization II

HL 68.3: Vortrag

Donnerstag, 19. März 2020, 15:30–15:45, POT 112

Size-effect of donors on the lattice parameters of wurtzite GaN — •Elias Kluth, Karsten Lange, Matthias Wienecke, Jürgen Bläsing, Hartmut Witte, Armin Dadgar, Rüdiger Goldhahn, and Martin Feneberg — Institut für Physik, Otto-von-Guericke-Universität Magdeburg, Germany

We present experimental results on the size effect of the donors Si and Ge in wurtzite GaN. Thin film samples grown by metal-organic vapour phase epitaxy on sapphire with (1120) surfaces were investigated by Hall-effect, high resolution x-ray diffraction, high resolution Raman spectroscopy, and infrared spectroscopic ellipsometry experiments. Phonons and lattice parameters were determined and systematic shifts as a function of carrier and donor concentrations were found.
Several contributions are considered: i) epitaxial strain due to epitaxy on foreign substrates, ii) influence of electrons on the lattice parameters, iii) the effect of donor ions on the surrounding GaN matrix which is the so called "size-effect". By comparing GaN:Si with GaN:Ge but similar carrier concentrations, we are able to distangle the different contributions. We report quantitative results of the size-effect of Ge and Si in GaN and phonon deformation potentials for several phonon modes.