Dresden 2014 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 107: Poster: Emerging oxide semiconductors / Oxides other than ZnO and its relatives

HL 107.17: Poster

Donnerstag, 3. April 2014, 17:00–20:00, P1

Structural and electrical investigations of Si-doped (In_xGa_1−x)₂O₃ thin films — •Anna Werner, Stefan Müller, Holger von Wenckstern, and Marius Grundmann — Universität Leipzig, Semiconductor Physics Group, Institut für Experimentelle Physik II, Leipzig, Germany

For the realization of solar-blind photodetectors the semiconductor β-Ga₂O₃ is due to the large band gap E_g of 4.9 eV especially suitable. Alloying β-Ga₂O₃ with indium allows to decrease E_g significantly and allows to control E_g and makes wavelength-selective photo detectors feasible. In this contribution we present structural and electrical properties of (In_xGa_1−x)₂O₃ thin films grown by pulsed laser deposition on c-plane saphire substrate in dependence of the alloy composition. For our investigations we used a wafer having a continuous composition spread. The In content varies between x = 0.008−0.69. Additionally the wafer is doped with 0.1% silicon to improve the electric conductivity. The lateral composition gradient was realized by ablating a segmented PLD target [1]. The thin film has monoclinic crystal structure and is (-201) oriented. The incorporation of In increases the spacing between (-201) planes. Transmission measurements exhibit a decrease of E_g with increasing In content. We investigated the properties of Schottky contacts fabricated in front-front geometry on a stripe of the wafer containing the complete range of In compositions. For that we used reactively sputtered PdO_x Schottky contacts and determined their characteristic parameters in dependence on the In content.

[1] H. von Wenckstern et al., CrystEngComm. 15, 10020 (2013)