Dresden 2014 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 32: Poster: ZnO and its relatives
HL 32.3: Poster
Montag, 31. März 2014, 17:00–20:00, P2
Electrical and optical properties of (Mg,Zn)O:Al thin films for solar cell application — •A. Mavlonov, H. von Wenckstern, S. Richter, R. Schmidt-Grund, and M. Grundmann — Universität Leipzig, Institut für Experimentelle Physik II, Linnéstr. 5, 04103 Leipzig, Germany
We investigated electrical, and optical properties of MgxZn1−xO:Al thin films in dependence on the aluminum concentration. For that we used a thin film with two perpendicular, lateral composition gradients (of Al and Mg, respectively). The sample was grown by pulsed-laser deposition (PLD) using a single but threefold segmented PLD target [1]. The spatial variation of chemical composition was investigated by energy dispersive X-ray (EDX) spectroscopy. The free carrier density and the mobility were determined by Hall-effect measurement. For a fixed Al concentration the bandgap increases systematically with increasing Mg content, and the plasma frequency, determined from IR spectroscopic ellipsometry decreases due to an increase of the effective electron mass. As expected, increasing the Al dopant concentration led to an increase of the free carrier density (varying between 2−9×1020 cm−3) and conductivity, and a minor decrease of the mobility. The absorption edge increases also with increasing Al concentration due to the Burstein-Moss effect. The reduced electron mass was calculated for different Mg content x, being 0.62me, 0.71me and 0.78me for x=0.01, 0.03 and 0.05, respectively.
[1] H. von Wenckstern et al.: CrystEngComm 15, 10020-10027 (2013).