Berlin 2015 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 100: ZnO and its relatives
HL 100.10: Vortrag
Freitag, 20. März 2015, 12:00–12:15, EW 203
The influence of Al and Ga dopants on the structural, electrical and optical properties of (Mg,Zn)O thin films grown by PLD — •Abdurashid Mavlonov, Steffen Richter, Holger von Wenckstern, Rüdiger Schmidt-Grund, Michael Lorenz, and Marius Grundmann — Universität Leipzig, Institut für Experimentelle Physik II, Linnéstr. 5, 04103 Leipzig, Germany
We have investigated structural, electrical and optical properties of Al- and Ga-doped (Mg,Zn)O thin films in dependence on the doping and alloy concentration. For this purpose, the samples have been prepared with two perpendicular, lateral composition gradients (Mg composition is varied in one direction whereas the Al/Ga concentration is varied in a perpendicular direction) [1]. The thin films were grown by pulsed-laser deposition (PLD) using a threefold segmented PLD target, a growth temperature of 600∘C and 2-inch in diameter c−plane sapphire substrates. With increasing free charge carrier concentration NHall in a range from 1×1019 to 3×1020 cm−3, the dielectric functions (DF) of the films show drastic changes due to increased (a) free-carrier absorption in the infrared region and (b) the Burstein-Moss effect in the ultraviolet region [2]. It has been found that the dopant efficiency and mobility tend to decrease with increasing Mg content, showing significant dependence in the case of Ga-doped films which can be explained with increasing the density of acceptor like compensating defects.
[1] H. von Wenckstern et al.: CrystEngComm 15, 10020 (2013).
[2] H. Fujiwara and M. Kondo, PRB 71, 075109 (2005).