Hetroepitaxy of III-nitrides on polycrystalline and amorphous substrates
III-nitride semiconductors, GaN, in particular, had played an important role in optoelectronic and electronic devices through the advancement of heteroepitaxy. These heteroepitaxy processes have been well established on single-crystalline substrates, such as Si, SiC, and sapphire. However, the mismatch between GaN and these substrates in lattice constant as well as thermal expansion coefficient imposes the limit on device performance and reliability. The search for a better substrate still continues. Here, we report the heteroepitaxy of III-nitride semiconductors on polycrystalline and amorphous substrates using a layered two-dimensional material as a buffer and seed layer. The two-dimensional material on a polycrystalline or amorphous substrate mitigates the lattice mismatch conditions, and shields the random oriented atomic registry of polycrystalline or amorphous substrates to promote single-crystalline hetroepitaxy of III-nitrides without any requisites from the substrate itself.
National Central Univ. (Taiwan)