Dresden 2017 – wissenschaftliches Programm
HL 25.15: Poster
Montag, 20. März 2017, 15:00–19:00, P2-OG2
Investigation of electrical conduction mechanisms in Si-doped GaN — •Stefan Kammer1, Klaus Irmscher2, Frank Mehnke1, Tim Wernicke1, Johannes Enslin1, Norman Susilo1, Martin Guttmann1, Luca Sulmoni1, Matthias Bickermann2, and Michael Kneissl1,3 — 1Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstr. 36, 10623 Berlin, Germany — 2Leibniz-Institut für Kristallzüchtung, Max-Born-Str. 2, 12489 Berlin, Germany — 3Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12480 Berlin, Germany
The electronic properties of Si-doped GaN grown by metal-organic vapor phase epitaxy with various doping concentrations were investigated by temperature dependent Hall-effect measurements. In contrast to the commonly described behavior of n ∝ exp( −EA/kBT ), the data show an increase of the Hall carrier density below 50 K. This implies the presence of multiple conduction mechanisms, requiring a more complex evaluation of the Hall carrier density. For this reason, a model considering carrier densities and mobilities from different conduction mechanisms has been applied in order to extract donor and acceptor concentrations as well as ionization energies from the Hall data. To determine the concentrations of Si and background impurities SIMS measurements have been performed. The influence of donor concentration and the effects of impurity conduction and interface charges on the temperature dependent charge carrier density will be discussed.