Ultrafast Carriers Dynamics Of Crystalline Silicon Film In Biosensor Base Material

With the continuous development of bio-nanotechnology,the continuous miniaturization of the size of biosensors has led to a continuous development in the performance requirements for materials.Crystalline silicon is widely used as the most classical semiconductor materials in different types of biosensors to achieve fast photoelectric response.Crystalline silicon films can achieve higher speed due to the unique properties of nanomaterial.The study of the ultrafast dynamics of carriers on the surface of crystalline silicon thin film can analyze the thermal transport mechanism of carriers inside the film more deeply.It can improve the response time of the material.It is also a certain significance on improving the manufacturing precision and sensitivity of the sensor.In this study,a femtosecond laser amplifier was used as the light source.The laser pulse width was 120 fs.The pump light was 400 nm and the probe light was 800 nm.They were used to study the transient reflectance change of a crystalline silicon thin film with a thickness of 1000 nm using the transient reflection experiment technique.The main research contents are as follows:A femtosecond laser transient reflection experiment system was set up to measure the transient reflectance changes of the crystalline silicon film under different single pulse energies,and the change law of transient reflectance was analyzed.Using the double-decaying index model to fit,the fast relaxation times under different pulse energies are obtained,and the ultra-fast dynamic response mechanism of reflectance changes is analyzed.The effects of different pump light energy laser pulses are analyzed.Ultra-fast dynamics of carriers on the surface of crystalline silicon films;The TTM-Drude model of femtosecond laser acting on single crystal silicon thin film was established.The changes of electron temperature and lattice temperature after the interaction of femtosecond laser and single crystal silicon thin film were analyzed.Different pulse energy was obtained.The role of download flow temperature and lattice temperature curve,calculate the carrier and lattice thermal equilibrium time,and analyze the physical process of rapid relaxation.