Charge-mediated remote epitaxy of Ga2O3 via MoS2

Abstract

Remote epitaxy of the corundum phase α-Ga₂O₃ is demonstrated through a domain-free, transfer-free monolayer of MoS₂ template synthesized on sapphire. Despite the intrinsic nonidealities of MoS₂—specifically its thickness and polar bonding characteristics—for remote epitaxy, single-crystalline α-Ga₂O₃ films are epitaxially grown on polycrystalline MoS₂ with crystallographic fidelity comparable to those grown directly on bare sapphire. This observation substantiates that the substrate lattice potential can still be effectively transmitted through the MoS₂ layer, facilitating epitaxial registry at the growth front. The resulting α-Ga₂O₃ films exhibit crystal quality and surface morphology on par with those grown directly on bare sapphire. Moreover, a centimeter-scale, crack-free α-Ga₂O₃ membrane was successfully exfoliated using a Ni stressor, underscoring the mechanical compatibility and scalability of the remote epitaxial process. Structural disordering observed with more-than-bilayer MoS₂ further corroborates the remote epitaxy mechanism. First-principles calculations reveal that interfacial interactions between the bottom S atoms of MoS₂ and the Al atoms of sapphire induce spatially modulated charge distributions on the MoS₂ surface, creating energetically favorable adsorption sites for Ga species. Collectively, these findings establish a mechanistic framework for charge-mediated remote epitaxy across polar interfaces and expand the design space for heterogeneous integration of transferable wide bandgap Ga₂O₃ membranes in next-generation power electronics and optoelectronic devices.