Dresden 2011 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 48: ZnO: Devices
HL 48.1: Talk
Wednesday, March 16, 2011, 10:15–10:30, POT 151
Optimization of optical and electrical properties of room temperature deposited ZnO:X (X = Al, Ga, In) TCO electrodes — •Tobias Diez, Alexander Lajn, Holger von Wenckstern, and Marius Grundmann — Universität Leipzig, Fakultät für Physik und Geowissenschaften, Institut für Experimentelle Physik II, Linnéstr. 5, 04103 Leipzig
Transparent conductive oxides (TCOs) are commercially exploited as electrodes in transparent electronics (e.g., transparent displays) and optoelectronic device applications (e.g., thin-film solar cells). Indium-tin-oxide (ITO) has the biggest market share, however, the increasing usage of TCOs in connection with the high indium price demands to establish alternatives. Doped ZnO is such a promising and cheap alternative to ITO. We deposited smooth, amorphous ZnO thin films on quartz glass and sapphire substrates at room temperature using pulsed laser deposition (PLD). To optimize the optical and electrical properties we measured transmittance and conductivity as a function of the oxygen pressure applied during PLD. Additionally, we investigated the influence of different group III dopants (Al, Ga, In) and their doping concentration on these thin film properties. For Al-doped ZnO the highest figure of merit (T10 / Rs = 1.9 · 10−3 Ω−1) was found at an oxygen pressure of 0.002 mbar and a doping concentration of 3 %. Furthermore, we analyzed the impact of this optimized growth condition on the device performance of transparent metal-semiconductor field-effect transistors (MESFET) using highly conductive ZnO as source and drain electrodes.