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HL: Fachverband Halbleiterphysik

HL 45: HL Posters III

HL 45.63: Poster

Donnerstag, 4. April 2019, 18:30–21:00, Poster E

Optimization of the Contact Resistance for Conductance Spectroscopy — •Mario Werner Farny, Carsten Ebler, Andreas Dirk Wieck, and Arne Ludwig — Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstraße 150, D-44780 Bochum

The development of time resolved conductance spectroscopy enhanced the possibilities to investigate two-dimensional electron gases (2DEG) coupled to Quantum Dots [1]. It allows time resolved observation of Quantum Dot charging dynamics. For this, modulation doped field effect transistor structures are made and measured at cryogenic temperatures. The success of the measurements depends on the highest possible response current of the 2DEG and a good signal to noise ratio. To ensure this, the source and drain contact resistance should be low.

We present results of the influence of various device processing steps. In particular, the influence of wet-chemical etching to reduce the distance to the 2DEG, as well as the necessity of wet-chemical surface passivation will be presented.

[1] Marquardt B. et al. Using a two-dimensional electron gas to study nonequilibrium tunnelling dynamics and charge storage in self-assembled quantum dots. Appl. Phys. Lett. 95, 022113 (2009).