  With the best overall electronic and thermal properties, single crystal
diamond (SCD) is the extreme wide bandgap material that is expected to
revolutionize power electronics and radio-frequency electronics in the future.
However, turning SCD into useful semiconductors requires overcoming doping
challenges, as conventional substitutional doping techniques, such as thermal
diffusion and ion implantation, are not easily applicable to SCD. Here we
report a simple and easily accessible doping strategy demonstrating that
electrically activated, substitutional doping in SCD without inducing
graphitization transition or lattice damage can be readily realized with
thermal diffusion at relatively low temperatures by using heavily doped Si
nanomembranes as a unique dopant carrying medium. Atomistic simulations
elucidate a vacancy exchange boron doping mechanism that occur at the bonded
interface between Si and diamond. We further demonstrate selectively doped high
voltage diodes and half-wave rectifier circuits using such doped SCD. Our new
doping strategy has established a reachable path toward using SCDs for future
high voltage power conversion systems and for other novel diamond based
electronic devices. The novel doping mechanism may find its critical use in
other wide bandgap semiconductors.
