p-Type Doping of GaN Nanowires Characterized by Photoelectrochemical Measurements.
GaN nanowires (NWs) doped with Mg as a p-type impurity were grown on Si(111) substrates by plasma-assisted molecular beam epitaxy. In a systematic series of experiments, the amount of Mg supplied during NW growth was varied. The incorporation of Mg into the NWs was confirmed by the observation of donor-acceptor pairs and acceptor-bound excitons in low-temperature photoluminescence spectroscopy. Quantitative information about the Mg concentrations was deduced from Raman scattering by local vibrational modes related to Mg. In order to study the type and density of charge carriers present in the NWs, we employed two photoelectrochemical techniques, open-circuit potential and Mott-Schottky measurements. Both methods showed the expected transition from n-type to p-type conductivity with increasing Mg doping level, and the latter characterization technique allowed us to quantify the charge carrier concentration. Beyond the quantitative information obtained for Mg doping of GaN NWs, our systematic and comprehensive investigation demonstrates the benefit of photoelectrochemical methods for the analysis of doping in semiconductor NWs in general.
Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7, 10117 Berlin, Germany.
Jumpei
0000-0003-3465-9869
J
Kamimura
Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institute for Solar Fuels , Hahn-Meitner-Platz 1, 14109 Berlin, Germany.
Peter
P
Bogdanoff
Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7, 10117 Berlin, Germany.
Manfred
M
Ramsteiner
Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7, 10117 Berlin, Germany.
Pierre
P
Corfdir
Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7, 10117 Berlin, Germany.
Felix
F
Feix
Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7, 10117 Berlin, Germany.
Lutz
L
Geelhaar
Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7, 10117 Berlin, Germany.
Henning
H
Riechert
GaN; MBE; Mg doping; Raman spectroscopy; nanowires; photoelectrochemical