Research On The Influence Of Dislocation On The Carrier Transport Characteristics Of HgCdTe In Infrared Detector

Infrared detecting device is the core component of target recognition for modern military weapons and equipment.Mercury Cadmium Telluride(HgCdTe)material has the characteristics of adjustable band gap width and widest detection wavelength range and maintain a leading position in the field of infrared detection.It's carrier transport characteristics directly limit the detection performance of infrared detectors.During the manufacturing,assembly and operation of the HgCdTe low-temperature infrared detector,the lattice mismatch and thermal mismatch problems have caused a large number of dislocations inside the HgCdTe material,which greatly damaged the symmetry and ordering of the crystal structure and seriously affected the transport characteristics of material carriers.For HgCdTe low-temperature infrared detectors,accurately determining the transport performance of downloaded carriers at different temperatures is a prerequisite for predicting and optimizing the performance of the detector device,so it is essential to establish a model that can quantitatively describe the transport characteristics of carriers.However,the existing theoretical research work on the carrier transport characteristics of HgCdTe materials has less consideration of dislocations,and there is a large gap between the prediction results of the model and the experimental law,resulting in the relevant model cannot accurately describe the carrier transport characteristics of the infrared detector in operation.Therefore,in this paper,the carrier recombination model considering the effect of dislocation recombination and the carrier scattering model considering the effect of dislocation scattering are established respectively.The main work and conclusion of the paper can be divided into two parts:1 ? A carrier recombination model of HgCdTe material considering the effects of dislocations was established,and the carrier lifetime of HgCdTe material was calculated.Compared with existing models,the prediction results of the model in this paper are in good agreement with the experimental measurement data of different HgCdTe samples reported in many literatures,and can accurately describe the evolution of the carrier life of different Cd components with temperature under the same set of parameters.This indicates that the carrier recombination model established in this paper can accurately characterize the carrier transport characteristics of HgCdTe material.The study also found that dislocations are one of the important factors that limit the lifetime of carriers.The lifetime of carriers increases slowly with temperature and then decreases rapidly.As the density of dislocations increases,the carrier lifetime decreases rapidly due to the enhancement of dislocation recombination.The results show that dislocations play an important role in the carrier recombination process in HgCdTe material and must be considered in modeling.2?A carrier scattering model of HgCdTe material considering the dislocation scattering mechanism was established,and the effect of dislocations on carrier scattering and mobility was quantitatively analyzed.The calculation results reveal the change law of carrier scattering rate and mobility with temperature.The study found that dislocation scattering is one of the main scattering mechanisms in materials with high dislocation density,which determines the carrier mobility together with other mechanisms;with the increase of dislocation density,the dislocation scattering mechanism will surpass the scattering mechanism of ionized impurities to become the dominant scattering mechanism,and the carrier mobility will be reduced;with the increase of temperature,carrier mobility increases first and then decreases,and the peak lifetime is just within the operating temperature range of the detector.The simulation results show that dislocation plays an important role in the carrier scattering process in HgCdTe material,which should be considered in the modeling.The above results have deepened the understanding of carrier transport mechanism in HgCdTe and improved the theoretical study of carrier recombination and scattering.By analyzing the physical behavior of dislocation defects in the material,a reasonable explanation was made for the experimental results of long-wave HgCdTe detection material.It has important guiding significance to accurately predict the quality factor,detection rate responsivity and other parameters of the device,and it also provides the necessary theoretical basis and reference for analyzing,evaluating and improving the detection performance and design of the device and improving the structure of the device.The carrier recombination model and scattering model established in this paper can be extended to other infrared detection materials,and the processing methods for dislocations in modeling provide reference research ideas for processing other types of defects.