Design And Optimization Of Silicon-based Nanowire Array Photodetectors Operating In The Optical Telecommunication Wavelength Band

Silicon-based photonics is a research hotspot in the field of semiconductor optoelectronics.As the core device of photoelectric conversion in silicon-based photonics,silicon-based near-infrared photodetectors have broad application prospects in high-speed optical communication system and on-chip optical interconnection.?-? family photodetectors are one of the most mature and best performance near-infrared photodetectors,but the lattice mismatch and thermal mismatch between ?-? family materials and silicon seriously limit the development of silicon-based ?-? family photodetectors.Semiconductor nanowires have strong stress release ability and excellent anti reflection properties,which have important application potential in high-performance silicon-based near-infrared photodetectors.In this paper,based on the in-depth study of the working mechanism of nanowire photodetectors,a silicon-based ?-? family nanowire array photodetector with a response wavelength of 1.55?m was designed,and its main performance was studied.The main results are as follows:(1)A silicon-based InP/In0.53GaAs0.47/InP p-i-n thin film photodetector was designed and its photoelectric characteristics were simulated.The results show that thin film photodetectors have high reflectivity in the wavelength range of 1-1.8 ?m,and the light absorption rate of incident light is only 23%in the thickness of nearly 800 nm.The responsivity is 0.43A/W when the bias voltage is-1V and the incident light power is 2.5×10-9W.(2)A radial p-i-n junction photodetector based on InP/In0.53GaAs0.47/InP nanowires was designed,and its spectral absorption and photoelectric conversion characteristics were simulated.The results show that the absorption spectrum of nanowire array strongly depends on its D/P ratio and diameter.The absorption peak can be fixed at 1.55?m by adjusting the combination of D/P ratio and diameter.The device has nearly 90%of absorptance rate at 1.55?m with a diameter of 360nm and a D/P ratio of 0.5,and at-1V bias,the device has a response of 0.9A/W,which is 5 times higher than that of thin film photodetectors with the same equivalent thickness.This is mainly due to the excellent anti reflection characteristics and light trapping effect of nanowire arrays.(3)A axial p-i-n junction photodetector based on InP/In0.53GaAs0.47/InP nanowires was designed,and its spectral absorption and photoelectric conversion characteristics were simulated.Similar to the radial p-i-n structure,the absorption peak can be fixed at 1.55 ?m by adjusting the combination of D/P ratio and diameter.Under-1V bias,the maximum responsivity of the device is 0.92A/W at 1.55?m with a diameter of 340nm and a D/P ratio of 0.4,which is slightly higher than the radial p-i-n structure with the same D/P ratio,and 7.7 times higher than that of the thin film photodetector with the same equivalent thickness.