Berlin 2018 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 33: Poster Session III
HL 33.23: Poster
Wednesday, March 14, 2018, 17:30–19:30, Poster F
Inverted HEMT structure with electric field induced 2DEG — •Ismail Bölükbasi, Julian Ritzmann, Andreas D. Wieck, and Arne Ludwig — Ruhr-Universität Bochum, D-44780 Bochum, Germany
Two-dimensional-electron gases (2DEG) have interesting physical properties and allow studies in reduced dimensions. For example they can function as a host material for electrostatic qubit systems, like quantum dots. These 2DEGs are mostly created in high-electron-mobility transistors with modulation doping.
However, there are deep donor levels, that hinder compatibility with photonic applications. Approaches like short-period-superlattice doping[1] lead to unwanted gate hysteresis. All structures seem to be plagued by charge noise, probably arising from the dopands in the modulation doped region. To avoid the interference with the impurities, the 2DEG can alternatively be induced with an electric field.
An issue with these structures is to produce reliable ohmic contacts to the 2DEG without short-circuits to the inducing gate. Here we use an approach with alloyed ohmic contacts to a global backgate, inducing the 2DEG. The 2DEG is then contacted with non-alloyed epitaxial contacts.
Umansky, V., et al. “MBE growth of ultra-low disorder 2DEG with mobility exceeding 35*106cm2/Vs.” Journal of Crystal Growth 311.7 (2009): 1658-1661.