Research On PIN Photodetector Based On Plasma Composite Micro-structure Silicon

The traditional silicon-based PIN photodetectors are limited by the high reflectance on the surface of Si,and the absorption of light with wavelength above 1.1 μm is almost0.The peak responsivity is about 0.5 A/W,and the responsivity at the wavelength of 1060 nm is only about 0.23 A/W,which cannot meet the needs of people.In order to break through the limitation of silicon materials,the combination of Black silicon(B-Si)material and gold nanoparticles is selected to make up for the deficiency of traditional silicon materials.While B-Si can reduce the reflectivity of silicon surface,S doping can increase the absorption of near infrared light of silicon material.Au NPs are deposited on the surface of B-Si,and the Local Surface Plasmons effect generated by Au NPs under the optical field is used to compensate for the decrease in the absorption rate of B-Si at wavelengths above 1100 nm.This thesis combines theory,simulation,and experiment.Firstly,the structure design of the plasma composite microstructure silicon PIN device was carried out;Then,simulation analysis and structural optimization of the new device were completed,and the plasma composite B-Si material was modeled and simulated,and optical analysis was conducted;In the experiment,excellent performance B-Si was prepared using femtosecond laser etching method,and Au NPs were deposited on the black silicon surface to make up for the decrease of near infrared light absorption.Finally,the plasma composite micro-structure silicon PIN device was fabricated and the key parameters were tested.The main research results of this paper are as follows:1.The structure of the new device is designed,and the plasma composite microstructure silicon material layer is introduced into the front photosensitive area of the positive PIN device.The device simulation of the designed B-Si PIN device shows that the peak responsivity of the device reaches 0.717 A/W,which is 0.22 A/W higher than that of the traditional PIN device.At 1060 nm wavelength,the device responsivity is 0.457A/W,which is 0.246 A/W higher than that of the traditional PIN device.The device structure design is reasonable.2.Through modeling and simulation of black silicon material,it is found that the higher the microstructure height of B-Si material,the better the anti-reaction effect of surface.The random distribution of Au NPs on the surface of B-Si shows that the higher the number of Au NPs deposited,the more obvious the near-infrared absorption enhancement of B-Si.When the number of Au NPs is constant,the larger the diameter of Au NPs deposited,the more obvious the near-infrared absorption enhancement of B-Si material is.3.B-Si materials with excellent properties were prepared by femtosecond laser etching.The average absorption rate of B-Si materials at 1100～2500 nm band was 90.11%,and the average absorption rate at 400～2500 nm band was 92.9 %.The average absorption rate of Au NPs/ B-Si was increased to 97.8 % at 1100～2500 nm and 98.04 % at 400～2500nm.4.The spectral response range of the novel plasma composite micro-structure silicon PIN device is 400～1190 nm,the peak response is 0.71 A/W(@990 nm,10 V),the maximum quantum efficiency is 92.2 %,the response at 1060 nm is 0.545 A/W,and the quantum efficiency is 63.7 %.The dark current is less than 20 nA.