Crystal growth is the core of integrated solid-state device technology, and the rise of 2D layered materials (such as graphene) has driven the demand for wafer-level scale and atomically thin single crystals of this unique type of device material to achieve compatibility with CMOS processes .
In view of this, recently, Stephan Hofmann and Oliver J. Burton (co-corresponding author) of the University of Cambridge in the United Kingdom have reported a method of using a standard cold-wall chemical vapor deposition (CVD) reactor to combine single crystal metal catalysts with graphite. Process flow of ene growth methods combined together. A sandwich structure is adopted between the commercial polycrystalline Cu foil and the c-plane sapphire wafer, and it has been shown that vacuum sublimation at a close distance in a limited gap can obtain a Cu(111) epitaxial single crystal film with a high growth rate.
This arrangement can realize wafer-level scale preparation and suppress the contamination of the reactor by Cu. Through time-of-flight secondary ion mass spectrometry, the newly prepared Cu thin film has high purity. By introducing hydrogen and gaseous carbon precursors, the initial metallization is seamlessly connected with the subsequent graphene growth, thereby eliminating the pollution caused by substrate transfer and the common lengthy catalyst pretreatment. The sandwich method can also obtain a Cu surface with nano-scale roughness during the growth of graphene, thereby producing high-quality graphene.
This article systematically explores the parameter space and discusses opportunities, including subsequent dry transfer, versatility, and versatility of the method, especially in the cost-effective way to prepare different monocrystalline film orientations and extend them to other materials System aspects.