Ultrafast Carriers Dynamics Of Nano-sized SnSe Film Studied

Nano materials have been widely used in the field of biology,which promotes the development of biological devices to high-speed response,micro and large capacity information storage.Semiconductor materials are widely used in the new biological direction,and nano size SnSe thin films are the best semiconductor materials to be used in the new nano biological devices due to their unique structure and mechanism,so as to achieve higher and more accurate response speed.In this paper,nanoscale SnSe films are prepared by pulsed laser deposition.The ultrafast dynamics of carriers in nanoscale SnSe films is studied by femtosecond laser pumping detection technology.The main research contents are as follows:1.Nanoscale SnSe films were prepared by pulsed laser deposition and characterized by XRD and XPS.2.The influence of pump light with different energy intensity on the transient transmittance of SnSe thin film in the pump probe experiment is studied and analyzed.The transient transmittance data under the action of different pulse laser intensity is obtained.The ultrafast carrier transport process in SnSe thin film is analyzed by the transmittance change law.The whole relaxation process can be divided into three parts:fast relaxation,middle relaxation and slow relaxation.3.The three relaxation processes are simulated by convolution model,and the relaxation time is calculated.The results show that the fast relaxation process of SnSe film is mainly the scattering process between carriers and the carrier phonon scattering process,which is affected by the defect state.The intermediate relaxation process is mainly the recombination of carriers,in which Auger recombination dominates and is affected by the defect state.The slow relaxation process is the carrier diffusion process.The model is fitted with the experimental data,which verifies the correctness of the conclusion.4.The ultrafast dynamics of downloaders with different pump energy is compared and analyzed.It is found that with the increase of pump energy,the initial carrier concentration becomes larger,the influence of defect state decreases gradually,the fast relaxation time becomes longer,and the whole relaxation process time becomes shorter.