Regensburg 2019 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 45: HL Posters III

HL 45.57: Poster

Thursday, April 4, 2019, 18:30–21:00, Poster E

Characterization of κ-(Al,Ga)₂O₃ Thin Films grown by VCCS PLD — •P. Storm, M. Kneiss, D. Splith, H. von Wenckstern, M. Lorenz, and M. Grundmann — Universität Leipzig, Felix-Bloch Institut für Festkörperphysik

Ga₂O₃ is a wide band gap semiconductor with E_g=4.4−5.3 eV depending on the respective polymorph [1]. Compared to the monoclinic β-phase, the orthorhombic κ-phase exhibits promising features like ferroelectic properties with high spontaneous polarization, possibly leading to the formation of 2DEGs with high electron densities at heterointerfaces. Alloying with Al allows band gap engineering, which is substantial for optoelectronic devices utilizing heterostructures, such as quantum well infrared photodetectors or modulation doped FETs and has therefore been investigated in this study. To achieve this, VCCS-PLD, a novel PLD method allowing the realization of vertical continuous composition spread (VCCS), has been utilized [2]. It enables direct control of the particle flux composition in the PLD plasma and the corresponding thin film compositions using a single radially-segmented target. Employing this technique, we have grown (Al,Ga)₂O₃ thin films (on c-sapphire substrates and MgO(111) buffer layers) with varying flux of tin in the PLD plasma to determine the critical content of this catalyst for κ-phase growth. Using the same technique, we varied the Al-content to investigate the structural and morphological impacts of Al in κ-phase Ga₂O₃.

[1] D. Tahara et al. : Appl. Phys. Lett. 112, 152102 (2018)

[2] M. Kneiß et al. : ACS Comb. Sci. 20 (11), pp 643-652 (2018)