The Influence of Surface Processing on the Surface Plasmonic Enhancement of an Al-Nanoparticles-Enhanced ZnO UV Photodectector

Abstract

Surface Plasmonic Resonance (SPR) induced by metallic nanoparticles can be exploited to enhance the response of photodetectors (PD) to a large degree. Since the interface between metallic nanoparticles and semiconductors plays an important role in SPR, the magnitude of the enhancement is highly dependent on the morphology and roughness of the surface where the nanoparticles are distributed. In this work, we used mechanical polishing to produce different surface roughnesses for the ZnO film. Then, we exploited sputtering to fabricate Al nanoparticles on the ZnO film. The size and spacing of the Al nanoparticles were adjusted by sputtering power and time. Finally, we made a comparison among the PD with surface processing only, the Al-nanoparticles-enhanced PD, and the Al-nanoparticles-enhanced PD with surface processing. The results showed that increasing the surface roughness could enhance the photo response due to the augmentation of light scattering. More interestingly, the SPR induced by the Al nanoparticles could be strengthened by increasing the roughness. The responsivity could be enlarged by three orders of magnitude after we introduced surface roughness to boost the SPR. This work revealed the mechanism behind how surface roughness influences SPR enhancement. This provides new means for improving the photo responses of SPR-enhanced photodetectors.

Emerging Schemes for Advancing 2D Material Photoconductive-Type Photodetectors

“…As mentioned above, the current metallic-nanostructure-based plasmonic optical antennas are cost-inefficient, and their plasmonic resonance spectra are commonly restricted to the range of ultraviolet to visible light, limited by the intrinsic properties of these materials [152,153]. Therefore, there is still an imperious demand to further explore new strat- Since the plasmonic resonance effect is predominantly determined by the material and structure of the optical antennas, and it has little relationship with the adjacent photosensitive channels, this improvement scheme can be conveniently applied to other 2DLMs, provided the working band matches the resonance band of the optical antenna.…”

“…As mentioned above, the current metallic-nanostructure-based plasmonic optical antennas are cost-inefficient, and their plasmonic resonance spectra are commonly restricted to the range of ultraviolet to visible light, limited by the intrinsic properties of these materials [152,153]. Therefore, there is still an imperious demand to further explore new strategies that can improve the light absorption of 2DLM photodetectors without compromising the preparation cost.…”