Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 92: Poster Session: II-VI Semiconductors & ZnO and related Materials
HL 92.19: Poster
Donnerstag, 29. März 2012, 16:00–19:00, Poster D
ZnO-ZnCo2O4-diodes — •Markus Winter, Friedrich Schein, Holger von Wenckstern und Marius Grundmann — Universität Leipzig, Institut für Experimentelle Physik II, Linnéstr. 5, 04103 Leipzig, Germany
The wide band gap semiconductor ZnO is a promising material for UV optoelectronic applications, photodetectors, front contacts of solar cells or transparent electronics. However, the growth of high quality p-type ZnO remains challenging. Therefore we investigated ZnCo2O4 as a suitable p-conducting oxide and fabricated semitransparent pn-diodes with n-ZnO.
The samples were grown by pulsed-laser deposition on a-plane sapphire substrates. We deposited ZnO:Al and ZnO at 680 ∘C and then amorphous ZnCo2O4 at room temperature, followed by dc-sputtered Au as ohmic contact. Transmittance of the ZnO/ZnCo2O4 layer structure is about 60%. The pn-diodes exhibit current on/off ratios (±2 V) up to 1010 and typically in the range of 107. Temperature-dependent current voltage measurements will be discussed. The spectral dependence of the photocurrent was determined and it was found that photocurrent is generated primarily in the ZnO-layer.