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arXiv · 2603.06845

Adsorption-Controlled Epitaxy and Twin Control of $\gamma$-GaSe on GaAs (111)B

Joshua Eickhoff·Wendy L. Sarney·Sina Najmaei·Daniel A. Rhodes·Jason Kawasaki
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Abstract

The III-Se layered semiconductors, including InSe and GaSe, are promising optoelectronic materials due to their relatively high electron mobilities at room temperature, nonlinear optical responses, ferroelectricity, self-passivated van der Waals surfaces, and ability to alloy and synthesize heterostructures for bandgap engineering. Adsorption control is a widely utilized strategy for controlling the stoichiometry and phase formation of these materials; however, the bounds of the adsorption-controlled growth window for GaSe have not been systematically established. Additionally, challenges with control over polytype and twinning remain. Here, we use molecular beam epitaxy to experimentally map the adsorption-controlled growth window of GaSe films on vicinal GaAs (111)B substrates. The observed phase boundaries show qualitative agreement with Ellingham diagram predictions. All films crystallize in the $\gamma$ ($R3m$) polytype. Increasing growth and annealing temperature leads to decreased mosaicity measured by x-ray rocking curve and smoother surfaces measured by atomic force microscopy, at the expense of a transition from singly oriented $\gamma$ to twinned $\gamma$ with $60\degree$ rotated domains.

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Joshua Eickhoff, Wendy L. Sarney, Sina Najmaei, Daniel A. Rhodes, Jason Kawasaki. 2026-03-06. Adsorption-Controlled Epitaxy and Twin Control of $\gamma$-GaSe on GaAs (111)B. https://arxiv.org/abs/2603.06845

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