Investigation On Surface Plasmon Enhanced Near- Infrared Light Photodetector

In recent years, the noble metal (e.g. Au and Ag) nanostructures have been widely employed to boost the performance of various optoelectronic devices including photovoltaic devices, photodetectors, waveguides, and so on. As alternatives to conventional noble metal, the plasmonic optoelectronic devices based on poor noble metal nanostructures (e.g. Cu, Al, etc.) have received increasing research interests due to their relatively low fabrication cost and tunable plasmon wavelength. It has been widely reported that the combination of plasmonic nanostructures with semiconductors offers a feasible route to improve the device performance of various optoelectronic devices. In addition, the highly localized electromagnetic field can generate energetic electron-hole pairs, which may surmount the potential barriers, leading to efficient hot injection from the plasmonic material to the semiconductor,therefore contributing to the photocurrent.In this study, we present a new plasmonic red light photodetector by decorating a multi-layer graphene-CdSe nanoribbon Schottky junction with a highly ordered plasmonic copper nanoparticle array.Herein, we have made a theoretical simulation for the optical properties of the CuNP array by the finite element method. We find that the plasmon properties were also different when the sizes of the CuNP array were changed. And with the change of the length and thickness of the particles, the copper nanoparticle array exhibited obvious localized surface plasmon resonance in the range of 700-900 nm. Based on the photoelectric analysis of the red light photodetectors before and after decorated with the plasmonic CuNP array, we find that after decorated with CuNPs, the photocurrent increased by about 24 times, from 0.124 to 3.1 mA. In addition, other device parameters including responsivity and gain were considerably enhanced. According to the theoretical simulation based on the FEM, such an optimized performance was benefited from hot electron injection induced by LSPR effect. These results show that the plasmonic CuNP arrays are promising candidates for improving the performance of optoelectronic devices.