Surface Plasmonic Silver Nanoparticle Enhanced Cu₂O Photodetector Properties

This paper start with the problems of Cu₂O based detector,for the traditional preparation technology,the existence of CuO impurities in the Cu₂O material,and the poor crystal quality and low hole concentration,lead to low photocurrent and low responsiveness of the Cu₂O detector.How to achieve a highly effective Cu₂O based detectors is becaming a hot topic.In this paper,we prepared Cu₂O thin films by electrochemical method and discussed the crystalline quality,surface morphology and other properties of Cu₂O thin films.The Cu₂O/ZnO heterojunction detector is fabricated,and the optical and electrical properties of the detector are tested.Finally,surface plasma is introduced to improve the response of the detector by surface plasmon resonance?SPR?.In this article,the main study include the following two parts:?1?By changing the deposition time,the effect of changing the deposition time on the the structure,crystalline quality,morphology of Cu₂O films which was prepared by electrochemical method was studied.The phase structure and the optical properties were examined by X ray diffraction and UV-vis spectrum.By comparing the result,the best growth conditions of Cu₂O films prepared by electrochemical deposition are deposition temperature is 60?,deposition voltage is-0.6V,value of electrolyte pH is 10,and deposition time is15min.The absorption edge of Cu₂O films prepared under this condition is about 560nm,crystallization quality is better,no impurities produce.This method has realized the preparation of high quality Cu₂O film.Through comparative analysis of I-V and response of Cu2O/ZnO detector,nonlinear analysis of I-V curves indicate that the Cu2O/ZnO detector formation of p-n junction,high light current and lower dark current show the detector overall good performance.?2?On the basis of the preparation of Cu₂O/ZnO detector under the optimal growth conditions by electrochemical deposition.Enhanced the performance of the detector is by Ag surface plasmon.The optimum size and distribution of Ag nanoparticles were obtained by theoretical simulation,and Ag nanoparticles were grown by ion sputtering,finally the matched growth conditions were obtained,and then Ag nanoparticles were added to the Cu2O/ZnO detector to improve the responsivity.The performance of the detector before and after added the Ag nanoparticles is introduced,and the enhancement mechanism is analyzed.The study shows that when the surface plasmon wavelength of Ag nanoparticles matches the Cu2O absorption peak,the absorption of incident light is enhanced by surface plasmon resonance coupling.Under 3V bias voltage,the maximum photocurrent is 3.8*10^-3A,the photocurrent intensity of Cu2O/Ag/ZnO nanoprisms is 10 times greater than Cu2O/ZnO detector.The photoresponse spectrum shows that the maximum response is 64mA/W at 3V bias voltage,which is 6 times higher than detector?11mA/W?without Ag particles.Cu2O detector with high responsivity has been obtained through surface plasmon enhancement.