Photoluminescence patterns via single-layer exfoliation in Gr/MoS2 heterostructure using contact-mode atomic force microscopy

Abstract

The stacking of two-dimensional (2D) materials presents numerous opportunities for various nanodevice applications. Achieving atomic-thick precision in microscopic patterning is crucial to manipulating the functionalities and interfacial interactions of the 2D heterostructures. In this study, a silicon atomic force microscopy (AFM) tip was utilized to rub the surface of graphene (Gr)/MoS2 heterostructure and manipulate its physical properties. The contact force between the AFM tip and Gr/MoS2 surface was adjusted between 110 and 660 nN. Before rubbing, the photoluminescence (PL) intensity of MoS2 was quenched due to the presence of Gr. After rubbing, the optical image and Raman spectroscopy acquired from the Gr/MoS2 heterostructure indicated that Gr started to be exfoliated by a contact force exceeding 220 nN. The absence of Gr due to exfoliation led to the restoration of MoS2′s pristine PL intensity. For demonstration, the AFM tip was used to exfoliate a designed micro-area covered with Gr using a 660 nN force, forming a patterned PL of MoS2. This technique enabled the creation of different structures to develop unique multilayer 2D material devices.