Regensburg 2007 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 46: Poster 2

HL 46.47: Poster

Thursday, March 29, 2007, 15:00–17:30, Poster A

Electrical Characterization of ZnO Microcrystals — •Andreas Rahm, Holger von Wenckstern, Jörg Lenzner, Michael Lorenz, and Marius Grundmann — Universität Leipzig, Fakultät für Physikund Geowissenschaften, Institut für Experimentelle Physik II,Linnéstr. 5, 04103, Leipzig, Germany

We report on the electrical properties of ZnO microcrystals with InGa as well as W ohmic contacts. Nanowires carry charge efficiently and are potentially ideal building blocks for future (opto)electronics. Knowledge about (metal) contacts and electrical conduction properties of ZnO is essential. We have investigated the temperature dependence of ohmic I-V characteristics for several different microcrystals. They were carbothermally grown at 1100 ^∘C and ambient pressure [1]. The measurements were performed with a semiconductor parameter analyzer (Agilent 4156C) in the dark in a helium cryostat. In the temperature regime from 200 K up to 300 K all samples show a strongly temperature dependent conduction. At low temperatures, i.e. in the freeze-out range there is an almost temperature-independent conductivity. Based on the assumption that the crystals exhibit a similar temperature dependence of the Hall mobility as bulk ZnO [2], it is possible to estimate the carrier concentration (1.22×10¹⁶ – 1.94×10¹⁷ cm⁻³) as well as the thermal activation energy (18 – 40 meV).

[1] M. Lorenz, J. Lenzner, E.M. Kaidashev, H. Hochmuth, and M. Grundmann, Ann. Phys. (Leipzig) 13, 39 (2004), [2] H. v. Wenckstern, S. Weinhold, G. Biehne, R. Pickenhain, H. Schmidt, H. Hochmuth, M. Grundmann, Adv. in Sol. Stat. Phys., 45 (2005).