Berlin 2024 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 13: Poster I
HL 13.29: Poster
Montag, 18. März 2024, 15:00–18:00, Poster E
Cation segregation in an (In,Ga)2O3 thin film library beyond the miscibility limit of the bixbyite structure — •Sandra Montag1, Daniel Splith1, Max Kneiß1, Marius Grundmann1, Javier Garcia Fernandez2, Øystein Prytz2, and Holger von Wenckstern1,2 — 1Felix Bloch Institute for Solid State Physics, Leipzig University, Germany — 2Department of Physics/Centre for Materials Science and Nanotechnology, University of Oslo, Norway
The transparent semiconductors In2O3 and Ga2O3 crystallise in different polymorphs. Hence, a phase change occurs in the alloy system of (In1−xGax)2O3, grown in bixbyite cubic structure at low x. To observe this change, a material library of thin films with 0.1 ≤ x ≤ 0.64 was fabricated by discrete combinatorial synthesis on r-plane sapphire substrates using pulsed laser deposition. The samples crystallize in the bixbyite phase for x ≤ 0.35, as revealed by X-ray diffraction. However, lattice constant and absorption edge energy systematically decrease and increase, respectively, with increasing Ga content only up to x = 0.2. For higher Ga admixtures, both saturate. In addition, a significant change in surface morphology occurs at x ∼ 0.2. Transmission electron microscopy examinations of selected samples show a homogeneous incorporation of Ga2O3 into cubic In2O3 for x = 0.11, while a segregation of Ga-rich and In-rich regions can be seen for higher x. In a sample with x = 0.35, the Ga-rich regions exhibit a preferred orientation, which has been shown to result from a correspondingly faceted In-rich bixbyite layer at the substrate-thin film interface.