2D material-based layer transfer and its applications for wafer-scale 2D/3D heterostructures

Jeehwan Kim
July 27th, 2018 JEEHWAN KIM

In recent studies, van der Waals epitaxy (vdWE) was investigated on 2D materials grown or transferred on arbitrary substrates, with the primary notion that the 2D material is the sole epitaxial seed layer in vdWE. However, the underlying substrate may still play a role in determining the orientation of the overlayers since the weak vdW potential field from 2D materials may barely screen the stronger potential field from the substrates. Moreover, previous water contact angle studies on the substrates with a graphene overlayer suggest that substrate contribution may exist. Here, we reveal that the epitaxial registry of adatoms during epitaxy can be assigned by the underlying substrate remotely through 2D materials by modulating the interaction gap between the substrate and the epilayer. Our study shows that remote epitaxial growth can be performed through a single-atom-thick gap defined by 2D material at the substrate-epilayer interface. We demonstrate successful remote homoepitaxy of (001) GaAs on (001) GaAs substrates through monolayer graphene. The concept is extended for remote epitaxy of other semiconductors such as InP, GaP, GaN and complex oxides through graphene and other 2D materials. The grown single-crystalline films are then rapidly released from the vdW surface of graphene. This concept, here termed 2D material based layer transfer (2DLT), suggests a method to copy/paste any type of semiconductors films from the underlying substrates through 2D materials then rapidly released and transferred to the substrates of interest. This works suggest new application space for 2D materials to save the high cost of non-Si substrates for advancing non-Si electronics and photonics. Lastly, I will discuss about our group’s effort on fabricating wafer-scale single-crystlaline 2D material heterostructures.

Seminar, July 27th, 2018, 12:00, Seminar Room

Hosted by Prof. Frank Koppens