Area-Selective Deposition of Germanium on Patterned Graphene/Molybdenum Disulfide Stacks

Advances in multi-dimensional structures via epitaxy techniques have revealed that two-dimensional (2D) materials can be substrates of the conventional semiconductors, called as three-dimensional (3D) materials, for economical manufacturing and delivering novel functionalities. Integration of 2D materials into the existing device architectures is a key approach for ‘More Moore’ and ‘Beyond Moore’. However, transfer of 2D materials onto the device architectures has been hindered by unintentional formation of wrinkles and absence of a way to remove the support media for the transfer. Therefore, direct growth of 2D materials on conventional materials and vice versa is a scalable and promising way to integrate 2D and 3D materials in an architecture. Growth of 3D materials on 2D materials has been hindered by low nucleation efficiency due to low density of surface dangling bonds on a 2D material. Here, we present area-selective deposition of germanium (Ge) on patterned graphene/MoS₂ stacks. Stacking graphene onto monolayer MoS₂ induces out-of-plane dipole moment due to charge transfer between the 2D materials. The out-of-plane dipole moment results in higher adsorption of germanium precursors. We performed density functional theory calculations of the out-of-plane dipole moment in the graphene/MoS₂ stack, chemical vapor deposition of Ge, and processing-dependent Ge nucleation behaviors on the graphene/MoS₂ stack.