| The fabrication of Reduced Graphene Oxide（RGO）,playing a key role in fabrication graphene with large scale and low cost,has excellent electrical and optical properties,could be controllably tuned by oxygen group.Therefore,RGO has been widely concerned in the field of photoelectric detection.Herein,based on the aim of improving the performance in photoresponse of RGO photodetector,changes in band structure of RGO,design and fabrication of detector device and improvements to device performance are all studied.The results are all as follows:（1）Rule in structure changing of RGO:In this paper,Graphene Oxide（GO）was prepared by Hummers method,GO film was prepared by sol-gel method,and RGO was obtained by annealing at high temperature.The structure of the material was characterized by thermogravimetric analysis,X-ray Diffraction（XRD）,Fourier transform infrared spectroscopy and other analysis methods.The changes of oxygen functional groups in RGO at different reduction temperatures were compared.The band gap in RGO reduction process was calculated by TAUC method.The nonlinear variation of RGO band gap from 1.9e V to 0.9e V was obtained.The reason for the change of band gap was that different oxygen-containing functional groups separated at a specific temperature range during the reduction process.（2）Design and fabrication of n-Si/RGO Semiconductor heterojunction photodetector:Here in,a heterojunction photodetector containing Si O2insulation layer was designed and fabricated,which showed superior rectification characteristic.Compared with the devices,which fabricated at different reduction temperatures,the maximum photoresponse wavelength was 450nm to 1310nm.The maximum on/off radio was more than 1900,the maximum responsivity was 0.12A/W and the magnitude of normalized detectivity was 1010.The increase of annealing temperature can effectively improve the characteristics of the device,which was consistent with the rule of band gap changing.（3）The improvement of device:Herein,different solution concentration and different substrate materials was studied,which could improve the device characteristics.Devices were fabricated by different solution concentration and different substrate materials,which showed that,high concentration of solution could effectively increase the light absorption,leading the improvement of the device performance.A heterojunction photodetector composed of n-GE and RGO was designed and fabricated.The photocarriers in the heterojunction of n-GE and RGO did not combine with the built-in electric field,which significantly improved the device characteristics,as a wide range of photoelectric response reaching 2200nm.This paper obtained the oxygen-containing groups of RGO tuned by annealing temperature and the rule of band gap changing.RGO devices were fabricated with different annealing temperature,which had different photoelectric detection capabilities,confirmed the rule of band gap changing in the macroscopical way.Also,a model of the physics mechanism was proposed to address the origin of the photocurrent.Our work pave a way to deeply apply RGO into electronic fields. |
