Epitaxial Substrate Having a 2D Material Interposer, Method for Manufacturing the Epitaxial Substrate, and Device Prepared from the Epitaxial Substrate

An epitaxial substrate having a 2D material interposer, the epitaxial substrate extending along an epitaxial interface direction, wherein the epitaxial substrate includes: a polycrystalline base substrate having a superficial layer, a wafer bevel, and a back surface, wherein a difference in coefficient of thermal expansion between the polycrystalline base substrate and MN or GaN is not greater than 1.5×106° C.−1 in a direction parallel to the epitaxial interface; a multi-orientation 2D ultra-thin material interposer arranged on the superficial layer of the polycrystalline base substrate, wherein the multi-orientation 2D ultra-thin material interposer has a top layer, a lattice constant of the top layer being highly matched with that of AlN, AlGaN, or GaN; and an AlN, AlGaN, or GaN-based epitaxial layer, which is epitaxially grown on a portion of the multi-orientation 2D ultra-thin material interposer distant from the polycrystalline base substrate.