Graphene-Mo2C heterostructure for highly responsive broadband photodetector

Photodetector based on intrinsic graphene can operate over a broad wavelength range with ultrafast response, but its responsivity is much lower than commercial silicon photodiode. The combination of graphene with two-dimensional (2D) semiconductors may enhance the light absorption but there is still a cutoff wavelength originated from the bandgap of semiconductors. Here we report a highly responsive broadband photodetector based on the heterostructure of graphene and transition metal carbides (TMCs, more specifically Mo2C). 2D graphene-Mo2C heterostructure has enhanced light absorption over a broad wavelength from ultraviolet to infrared range. In addition, there is very small resistance for photoexcited carriers in both graphene and Mo2C. Consequently, photodetectors based on graphene-Mo2C heterostructure delivers a very high responsivity from visible to infrared telecommunication wavelengths.