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 two-dimensional 2D material interposer, the epitaxial substrate extending along art epitaxial interface direction, wherein the epitaxial substrate comprises:

• 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 AlN or GaN is not greater than 1.5×10−6° 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.

A method for manufacturing an epitaxial substrate having a 2D material interposer, comprising:

• forming a continuous thin film comprising two types of crystalline domains matched with each other at an angle of 60° by growing a multi-orientation 2D ultra-thin material interposer on a surface of a hexagonal symmetrically structured single-crystal substrate, wherein a lattice constant of the continuous thin layer is highly matched with that of AlN, AlGaN, or GaN;
• transferring the multi-orientation 2D ultra-thin material interposer from the hexagonal symmetrically structured single-crystal substrate onto a superficial layer of the polycrystalline, base substrate;
• and
• growing epitaxially an AlN, AlGaN, or GaN-based epitaxial layer on the multi-orientation 2D ultra-thin material interposer to obtain the epitaxial substrate with a 2D material interposer.