Plasmonic Hot Carriers Transfer Enhanced Photodetector

The rapid development of physical and chemical preparation methods in the field of microstructure preparation makes plasmon which properties depend on the shape,size and surrounding dielectric constant of nanostructures quickly become a research hotspot in various subject areas.The local surface plasmon resonance in the metal-semiconductor heterojunction having an impact on the optoelectronic properties of semiconductor open a new avenue for the research on optoelectronic devices.At present,many optoelectronic devices based on metal-semiconductor heterojunctions increase the optoelectrionic efficiency through the hot carrier transfer mechanism.The plasmon generates hot carriers through non-radiative decay,and the energy and quantity of hot holes generated by gold nanoparticles?Au NPs?with a unique d-band structure are larger than of that hot electrons.However,the free path of hot holes is smaller than that of hot electrons resulting in the collection of hot holes being relatively difficult.This is the reason of most reports are plasmon hot electron transfer.From the standpoint of the plasmon hot holes transfer,the coupling between metal and p-type semiconductors is better than with n-type semiconductors.Cuprous oxide?Cu₂O?is a typical p-type semiconductor material.With the rapid development of isodynamics,the plasmon energy transfer of metal-semiconductor heterostructures has injected new vitality into the development of Cu₂O NWs.In metal-semiconductor heterostructures,the hot carriers induced by plasmon are transferred to neighboring semiconductors to generate photocurrents.This way of improving the photoelectric conversion efficiency opens a new way for the development of photodetectors.In this article,a novel plasmonic hot holes transfer enhanced photodetector based on Cu₂O-Au NWs was designed and fabricated.Parameters such as optoelectrionic conversion properties of the photodetector were studied,and the process of hot carrier transfer increasing photocurrent is analyzed.The main research are as follows:?1?Cu₂O NWs with an average diameter of about 177 nm were prepared by liquid-phase method under hydrothermal conditions.Au NPs with an average diameter of about 50 nm were prepared by seed method.The Cu₂O NWs photodetector were prepared by liquid-phase thin film assembly technology.On this basis,the Au NPs were coupled to Cu₂O NWs by liquid-phase deposition techniques to form Cu₂O-Au NWs photodetector.?2?Through the research and analysis of the output characteristic curve,it was found that the Cu₂O-Au NWs photodetector fabricated in this paper is p-type depletion mode.Through the study of the detection parameters of the photodetectors in the visible light,the results show relative to the Cu₂O NWs photodetector,the Cu₂O-Au NWs photodetector increase by an order of magnitude up to 0.314 A/W,an 18 times enhancement of external quantum efficiency at about 640 nm,an 15.4 times enhancement of signal to noise ratio up to 16.6 and a high detectivity of 3.6x10¹⁰ Jones about 17.7 times enhancement.These performance parameters increase with the increase of grid reverse bias voltage.The photo response speed of the Cu₂O-Au NWs FET photodetector increased to 4 times at the rising edge and the light response speed at the falling edge increased to 6.7 times.The hot holes in Au NPs are directly injected into the semiconductor and improve the carrier concentration of the semiconductor.As a result,the photoelectric conversion performance of Cu₂O-Au NWs photodetector is enhanced.Besides,the stability test of the Cu₂O-Au NWs photodetector was also carried out.It can be found that no significant decline of photocurrent under the light power of 11.575 mW/cm² and continuous working 5.5 h.The findings pave the way for new plasmonic hot carrier transfer device in optoelectronic application.