Study On Graphene Photodetector Based On Glass Waveguides

In the field of Integrated Optoelectronics,using ion exchange technology to fabricate optical waveguides based on glass has a lot of advantages,such as low transmission loss,low cost,less sensitive to wavelength,good stability and easy environment in system integration.It is suitable for mass production of integrated optical devices.As a new kind of two-dimensional material,Graphene has excellent optical and electrical properties.In addition,the research on the theory and optoelectronic devices has also made great achievements.The research work of this paper is mainly focused on the combination of glass waveguide structure and graphene,and the detectors based on glass waveguides are designed and fabricated successfully by using the unique optoelectronic properties of graphene.The working principle of the device is based on photoconductive effect.When the graphene absorbs the energy of photon in the waveguide,the electrons are excited from valence band to the conduction band to produce photogenerated carriers.It leads to the resistance of graphene decreasing and the light current increasing.Different light power incidenting on the device will produce different sizes of photocurrent,which make the photoelectric detection come true.The main contents of this paper are as follows:In this paper,we calculated the normalized ion concentration and diffusion depth,graphene conductivity,dielectric constant,carrier concentration and other basic physical parameters form the classical model of diffusion exchange of Ag+-Na+thermionic and graphene,On this foundation,a model of metal-graphene-metal photodetector was established and the photocurrent value was calculated.The performance of the graphene based photodetector is analyzed theoretically.Then,we designed two kinds of photoelectric detectors with different electrode structure,and expounds the reasonable process parameters under the experimental conditions through the exploration of the process.It lays a foundation for the successful fabrication of the photodetector and provides a basis for the fabrication of other optical devices based on the glass waveguides.In this paper,two devices with different electrode structures were tested.The test results show that when the bias voltage is 1V and the incident wavelength is in the range of 1500-1600 nm,the response of the devices have good steadiness and consistency.For the wavelength of incident light is 1550nm,the maximum response of the device with parallel electrode can reach 0.21 A/W,and the response of the device with interdigital electrode is 0.28A/W.Finally,the test results are analyzed from the aspects of conductivity,electric field intensity and migration rate,then compared with the theoretical simulation.The possible reasons for the similarities and differences between theory and experiment are discussed.