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Debarghya Sarkar1 Wei Wang1 Chenhao Ren1 Matthew Mecklenburg1 Andrew Clough1 Qingfeng Lin1 Rehan Kapadia1

1, USC, Los Angeles, California, United States

In this work, we demonstrate thermodynamically driven geometrically constrained wetting of liquid metal templates on diverse substrates, and utilize that to directly grow templated thin films of indium and tin based crystalline compound materials on a variety of epitaxial and non-epitaxial substrates through templated liquid phase (TLP) method. Based on the interfacial energies, a critical aspect ratio of templates exists, below which complete wetting of the template area occurs, and above which partial dewetting of varying extent takes place. This behavior has been verified with a thermodynamic model. This also allows us to reproducibly obtain templated thin films of pre-determined geometry of III-V (such as InP, InAs, InGaP) and IV-V (SnP, Sn3P4) compounds on an array of amorphous and crystalline ceramic substrates. Tuning the growth conditions ensures a single nucleation site in each template, resulting in single-crystal templates which have also been characterized with high resolution transmission electron microscopy. Micro-photoluminescence measurements of InP attest to the high optoelectronic quality of the grown material comparable to that of a single crystal commercial wafer. Tin phosphide of two different stoichiometries were obtained based on the growth temperature: SnP and Sn3P4, with distinct Raman, X-ray photoelectron, and absorbance spectra. Further, we obtained a lateral heterostructure of InP and Sn3P4, with a naturally formed atomically sharp interface between two distinctly different materials with widely different crystal structures. These demonstrations potentially mark the beginning of a new genre of material growth technique with increased opportunity for device and system design with novel functionalities.

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