| 초록 |
Bi-layer graphene, which is composed of two sheets of monolayer graphene, has different electrical and optical properties with monolayer graphene. In case of AB stacking structure, it has a tunalbe band gap with a perpendicular electric field. In otehr case that two sheets of monolayer graphene are stacked with twist angle, twisted bi-layer graphene, shows angle dependent electrical and optical properties, like van Hove singularity and photo current. However, it is difficult to synthesis of bi-layer stucture with precise angle and uniformity by CVD method so two sheets of monolayer graphene are synthesized individually and stacked each other by supporting layer. But during transfer process, the interface between graphene is contamination and the precise twist angle control is difficult. In this study, we introdcue the novel stacking method using van der Waals interaction that provides clean interface between graphene and precise twist angle control. By using gold pattern on monolayer graphene and PPC/PDMS stamp, we selective pick up the gold/graphene pattern and place on remain graphene. This pattern stacking method can fabricate bi-,tri- and more multi-layer graphene pattern by just one monolayer. Actually, in graphene device, it is small part to use part of graphene so we can fabricate device array of bi-, and multi-layer graphene by just one monolayer grapheme. Furthermore, we can fabricate the tunnel junction device by half overlap structure. So we expect that this stacking method can be easily used to fabricate various structure of van der Waals Heterostructure device. |
