Near-Infrared Graphene/4H-SiC Schottky Photodetectors

Abstract

Silicon Carbide (SiC), with its superior electronic properties, is recognized as one of the most promising candidates for the new generation of optoelectronic devices. In the present work, a preliminary study about a graphene/4H-SiC Schottky junction photodiode operating in the near-infrared (NIR) spectral range was performed. In particular, we report about the fabrication and the electro-optical characterization of the first - to the best of our knowledge - graphene/4H-SiC-based Schottky near-infrared photodetector. Ten devices, with the same geometry, were electrically characterized, the I-V plot shows a good rectifying behavior, with a series resistance of 60±23 Ω, an ideality factor of 7±1, and a zero-bias Schottky barrier height of 0.55±0.05 eV. Concerning the optical characterization, it was performed at the wavelength of λ=785 nm, which is far away from the absorption edge of the used wide bandgap semiconductor. The maximum internal responsivity without bias-voltage was evaluated as 0.12 mA/W. Even if the measured responsivity is still limited, we believe that this device can pave the way to investigations on near-infrared Schottky photodetectors based on graphene/4H-SiC junctions, useful for communications at the common fiber optic wavelengths.