▎ 摘　　要

Many material device applications would benefit from thin diamond coatings, but current growth techniques, such as chemical vapor deposition (CVD) or atomic layer deposition require high substrate and gas-phase temperatures that would destroy the device being coated. The development of freestanding, thin boron-doped diamond nanosheets grown on tantalum foil substrates via microwave plasma-assisted CVD is reported. These diamond sheets (measuring up to 4 x 5 mm in planar area, and 300-600 nm in thickness) are removed from the substrate using mechanical exfoliation and then transferred to other substrates, including Si/SiO2 and graphene. The electronic properties of the resulting diamond nanosheets and their dependence on the free-standing growth, the mechanical exfoliation and transfer processes, and ultimately on their composition are characterized. To validate this, a prototypical diamond nanosheet-graphene field effect transistor-like (DNGfet) device is developed and its electronic transport properties are studied as a function of temperature. The resulting DNGfet device exhibits thermally activated transport (thermionic conductance) above 50 K. Below 50 K a transition to variable range hopping is observed. These findings demonstrate the first step towards a low-temperature diamond-based transistor.