Understanding the Growth Mechanisms of γ-GeSe for Polymorph-Selective Large-Area Deposition

Abstract

Understanding the growth mechanisms of a newly discovered polymorphic material and achieving large-scale selective growth is critical for accurate material characterization and application. Post-transition metal monochalcogenides, including Ge chalcogenides, are known to exhibit various polymorphic configurations, and selectively growing a target metastable polymorph is challenging. This study delves into the growth mechanisms and polymorph-selective growth methods of gamma-phase germanium selenide (GeSe), a recently identified hexagonal polymorph. The role of the Au catalyst in the vapor-liquid-solid synthesis of gamma-GeSe is investigated in detail via crystallographic and morphological investigations of growth products as a function of Au catalyst size. Azimuthally-aligned gamma-GeSe flakes grow more efficiently and selectively on boron nitride and graphite templates, indicating the importance of the growth substrate. Chemical-vapor-deposited graphene-covered substrates allow for large-area growth of gamma-GeSe, leading to practical applications.,This work unveils the pivotal roles of Au catalysts and substrates in the polymorph-selective, large-area synthesis of gamma-GeSe. The demonstrated synthesis of gamma-GeSe will advance energy storage and optoelectronics applications with the new polymorph.,