All-carbon devices based on sp2-on-sp3 configuration

Carbon has around 500 allotropes, and most of them have excellent physical properties offering great potential for the development of electronic, optoelectronic, energy storage, and sensor applications. In the case of diamond and graphene/graphite, although the carbon atoms have different hybridization structures, their complementary characteristics and potential for direct conversion between them may open up opportunities for novel all-carbon device applications. Diamond and graphene/graphite have unique superior properties and good lattice matching between them so that the direct fabrication of high-quality graphene-on-diamond heterostructures enables the new development of a variety of ultrawide bandgap devices and chemical/bio-sensors. In this perspective, we introduce recent investigations into the formation of graphene films on diamond substrates through an in situ sp3-to-sp2 conversion process to enable their application to radiation detection/photo-electronics, high-power/high-frequency electronics, and chemical/biological sensing.