Berlin 2015 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 96: Poster III C (III-V Semiconductors incl. Nitrides)
HL 96.15: Poster
Thursday, March 19, 2015, 14:00–20:00, Poster B
GaN quantum dot ensembles for capacitance-voltage measurements — •Carlo A. Sgroi, Arne Ludwig, and Andreas D. Wieck — Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780 Bochum, Germany
GaN and its alloys have excellent properties regarding thermal stability at ambient conditions, high thermal conductivity and wide bandgap energies, thus making it an ideal candidate for high power and high temperature microelectronic devices.
The aim of this study is to design a heterostructure by MBE growth for measuring self-assembled GaN QDs on AlxGa1−xN by capacitance-voltage (C-V) spectroscopy. Whereas InAs - QDs on GaAs cease to exhibit their quantum character above a temperature of about T = 20 K, the higher bandgap of GaN will lead to a substantial higher working temperature of GaN - QDs.
GaN/AlxGa1−xN heterostructure layers in the wurzite structure have deformed band structures due to polarization effects induced by doping and strain which complicates the prediction about the band structure and electrical properties.
Band structure simulations were run to calculate a decent tunneling barrier for C-V measurements capitalizing on the polarization effect and the quantum dot conduction band minimum close to the Fermi energy. Therefore, different Al-contents in the adjacent heterostructure layers are required. To establish a lower polarization effect and the demanded band structure, the Al-content is graded linearly. C-V measurements will be presented for different configurations.