Research On The Interaction Between Carriers And Terahertz Waves In Semiconductors

Terahertz(THz)waves cover the frequency range of 100 GHz(ie 0.1 THz)to 10 THz in the electromagnetic spectrum,which is between microwave and infrared frequencies.In the past ten years,terahertz has received a lot of attention due to its many unique characteristics,and has broad application prospects in many fields such as phase detection,medical imaging,safety screening,and human security inspection.On the basis of achieving suitable terahertz wave sources and receivers,a large number of terahertz wave modulators are also needed to control the electromagnetic characteristics such as the amplitude,phase,and pulse length of the terahertz wave,so as to better apply the terahertz wave wave.In this thesis,we use the theoretical method of calculating the terahertz wave transmittance in the semiconductor carrier concentration,establish the MATLAB model to solve the terahertz wave transmittance,and analyze the influence of different semiconductor size,different carrier concentration on the terahertz wave transmittance.According to the general carrier motion equation of semiconductor,a MATLAB model for solving carrier distribution in a semiconductor terahertz wave light modulator under laser irradiation is established.The effects of laser wavelength and power on terahertz wave modulation are analyzed in detail.In addition,since surface plasmon resonance of metal nanoparticles can significantly increase the concentration of photogenerated carriers in the semiconductor,the effect of nanoparticles of different sizes on the laser intensity distribution is simulated in this paper.Moreover,a Matlab model was established to continuously solve the reaction,nucleation and growth process of liquid phase synthesis of nanoparticles.The effects of different synthesis conditions(reaction rate of chemical equilibrium reaction,solution diffusion coefficient,adsorption coefficient of nanoparticles,ambient temperature,heating rate,etc.)on the size distribution of nanoparticles were analyzed.