Researchs On Increasing The Absorption Efficiency Of Photodetector By Surface Plasma

In recent,the optical properties of micro-nano metal structures are a hot research focus in nanometer photonics.These micro-nano metal structures have great value in surface-enhanced raman sc,attering,medical diagnostics,and biochemical sensing,which includes nano-particles,nano-rods,nano-rings,and so on.And also create greater value for society.The optical properties of micro-nano metal structures are closely related to surface plasmon.By changing the material,shape,size and array period of the particles,the position of the surface plasmon resonance peak in the visible light range is changed,which provides a theoretical basis for the fabrication of nanophotonic device.The main work is as follows:1.In order to study the light absorption of surface plasmon-enhanced photodetector,the extinction characteristics of silver,gold and copper nanoparticles is first calculated and analyzed using the finite element method.Then,the effects of the size,shape,and array period of metal nanoparticles on the light absorption efficiency of the silicon photodetector is analyzed.The results show thatspherical nanoparticle arrays are used on the upper surface of the silicon photodetector,and the optimum SiO2 layer thickness is 60 nm.2.A silicon thin film photodetector structure with a spherical silver nanoparticle array on the upper surface is designed by using the effect of metal nanoparticles on the light absorption of photodetector.The results show that the key parameter affecting the light absorption efficiency of silicon films is the ratio of the period and diameter of the array,and then the effect of incident light angle on light absorption is discussed,and an optimum incident angle range is found to be 0 to 65 degrees.The results show that:Based on the finite element method,the effect of metal nanoparticles on the light absorption of photodetector is studied.The results show that the peak absorption decreases with the increase of the particle size,and the spherical nanoparticles have better absorption than ellipsoidal and square nanoparticles.Compared with the bare silicon photodetector,the plasmon photodetector increases the light absorption efficiency from 5%to 65%at an incident angle range of 0 to 65 degrees,and the photoelectric conversion efficiency increases from 29%to 34%.