Metal/TiO₂ Schottky Junction Hot Electron Photodetector Based On The Surface Plasmon

Hot electron photodetectors based on the surface plasmon have attracted significant attention in recent years.Because its photoelectric properties are not only related to semiconductor materials,but also through the rational design of metal micro-nano structures,such as changing its composition,shape,and dimensions,photoelectric conversion of the photonic with an energy lower than the material bandgap can be achieved,and the comprehensive performance of existing devices can be improved.This idea greatly expands the design scope of optoelectronic devices,and it is widely used in the fields of photocatalysis,photovoltaic,photodetection,etc.In this paper,the semiconductor material TiO₂ with wide bandgap is used as the research object,then the granular TiO₂-based Schottky junction hot electron photodetector with transparent electrodes of different metals was prepared by magnetron sputtering.By using plasmon resonance excited on the metal surface,the absorption spectrum of the photodetector is widened,and the performance of the photodetector is improved.The specific research work is mainly divided into the following two aspects:(1)The effect of the incorporation of Au nanoparticles on the performance of Au/TiO₂ Schottky junction hot electron photodetectors was studied.In this paper,Au nanoparticles were incorporated between Au transparent electrode and crystalline TiO₂,and the optical and electrical performance of the device can be adjusted by changing the size distribution of Au nanoparticles.Under the combined action of surface plasmon resonance and conformal structure transparent electrode with light trapping characteristics,the effective detection wavelength of the optimal device has been widened from 400 nm which only has a pure TiO₂ film to beyond 900 nm.At the same time,compared with the control device(without the incorporation of Au nanoparticles),the transient photocurrent at 850 nm is increased by 9.6 times,and the light absorption value is increased by1.4 times.In addition,the device works under zero bias and has good self-driving characteristics.(2)The effect of different metal transparent electrodes on the performance of Ti O2-based Schottky junction hot electron photodetector was studied.In order to further reduce the manufacturing cost and improve the performance of the photodetector,the metal transparent electrodes were changed into Ag and Cu,and keep the size of incorporating Au nanoparticles.The comparative study found that,the device with Ag transparent electrodes have better performance in the ultraviolet and visible light range,while the device with Au transparent electrodes have better detection capabilities for near infrared wavelength.Due to weak ability to excite surface plasmon,the device with Cu transparent electrodes have the poor ability to detect semiconductors in non-absorptive bands,and there is a gap with the other two metal materials.