Dresden 2014 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 32: Poster: ZnO and its relatives

HL 32.2: Poster

Monday, March 31, 2014, 17:00–20:00, P2

Low frequency noise in ZnO-based MESFETs — •Fabian J. Klüpfel, Holger von Wenckstern, and Marius Grundmann — Universität Leipzig, Fakultät für Physik und Geowissenschaften, Linnéstr. 5, 04103 Leipzig

We examined the sources of noise in metal-semiconductor field-effect transistors (MESFETs) based on n-type ZnO channels on a-plane sapphire substrates for frequencies up to 100 kHz. Measurements have been performed in dependence on the channel geometry prior and after gate deposition. The noise has also been characterized depending on the applied source-drain voltage. In addition to thermal noise a contribution with a 1/f power density spectrum can be observed at ZnO channels without gate, which is best described by a generation-recombination process in the semiconductor with a broad range of attributed time constants. To realize MESFETs we used reactively sputtered platinum Schottky contacts. The noise measured at ungated channels and at Schottky contacts was compared with the drain current noise of the transistors, in order to identify the dominating source of noise and its dependence on geometrical parameters. The results can be used to improve the signal-to-noise ratio in ZnO-based sensor applications.