Towards graphoepitaxy of semiconducting 2D single crystals on dielectric substrate patterns for next generation nanoelectronic devices

Semiconducting two-dimensional (2D) transition metal dichalcogenides like MoS2 and WS2 are attracting great interest for application in ultra-scaled nano-electronic devices because of their monolayer thickness, large band gap, low dielectric constants and lack of dangling bonds. A key prerequisite for their industrial exploitation is the availability of manufacturable deposition techniques like Chemical Vapor Deposition (CVD) to create semiconducting 2D monolayer crystals at wafer-scale. While epitaxial growth on monocrystalline templates ensures high quality 2D crystals, it requires an industrially incompatible transfer process from template to target substrate to enable device fabrication. On the other hand, direct growth on target dielectric substrates results in polycrystalline films with grain boundaries that degrade carrier mobility. The project’s ambition is to explore a novel pathway to grow semiconducting 2D single crystals by graphoepitaxy directly on dielectric substate patterns with topography. We will generate fundamental understanding of crystal growth for 2D WS2 and MoS2 during CVD and use that to design the topography of dielectric substrate patterns and choose optimal process conditions for graphoepitaxy. This method for direct growth is compatible with conventional nanoelectronic device fabrication flows and avoids a challenging transfer process. Moreover, this method broadens the application space of 2D semiconductors as it is compatible with 3D substrates.