Plasmonic graphene/perovskite Schottky barrier photodetector

Abstract

In this paper the performance of a graphene/perovskite Schottky barrier photodetector is investigated theoretically for detecting infrared radiation within the spectral region of 7.5–10 μm. In order to increase the responsivity of the photodetector plasmon–polaritons are excited in the graphene layer within the specified spectral region with the aid of dielectric grating fabricated inside the photodetector structure. The results show that with the increase of the Fermi energy level in the graphene layer the wavelength where plasmon–polaritons are excited is shifted toward shorter wavelengths. This property enables the photodetector for tunable detection. The excitation of plasmon–polaritons localizes the infrared radiation incident on the photodetector to the graphene layer with a full width at half maximum of ≈12.6 nm. This localization increases the absorbance of the graphene layer considerably at peak detection wavelengths where plasmon–polaritons are excited, so that at peak detection wavelengths the absorbance of the graphene layer inside the photodetector is higher than 20 % while without the excitation of plasmon–polaritons the absorbance of the same layer is below 0.05 %. Due to this effect the responsivities of the photodetector at wavelengths where plasmon–polaritons are excited, increase more than 535 times relative to the case where plasmon–polaritons are not excited. Therefore the excitation of plasmon–polaritons not only increases the responsivity of the photodetector significantly but also enables the photodetector for tunable detection by varying the Fermi energy level in the graphene layer.