Defect Engineering Of Two-Dimensional GaTe Materials By Ion Irradiation

For three-dimensional materials such as metals,the occurrence of defects is sometimes inevitable and can significantly affect various properties of the material.Investigating the relationship between these defects and material properties is of great significance for understanding the basic properties of materials.However,in threedimensional materials,it is necessary to introduce defects with high density to modulate their physical and chemical properties.In contrast,two-dimensional materials with atomic-level thickness are ideal for studying the relationship between defects and material properties.This project aims to use focused ion beam irradiation to introduce controllable local defects in two-dimensional gallium telluride(GaTe),and then to compare the changes in optical,electrical,and optoelectronic properties of the material before and after ion beam irradiation,in order to understand how defects modulate material properties.The main research contents are as follows:We first characterized the composition of the GaTe sample and determined the introduction of defects by focused gallium ion beam irradiation.Then,Raman spectroscopy was used to characterize the material,and a Raman peak not belonging to the material itself was observed in irradiated GaTe.The intensity of this Raman peak increased with increasing irradiation dose,indicating an increase in defect density.The production of defects in GaTe thin films also affected the photoluminescence,with the emission peak shifting to longer wavelengths with increasing irradiation dose.More excitonic emission peaks were also observed in low-temperature irradiated GaTe,indicating changes in the two-dimensional material’s band structure caused by the introduction of defects.The electrical properties of GaTe could also be effectively modulated by gallium ion beam irradiation.The conductivity of irradiated GaTe increased significantly,and the response to specific wavelengths of light was also greatly improved while maintaining a short response time.In addition,the introduction of defects allowed the GaTe field-effect transistor to break through the absorption wavelength limit and achieve photodetection in the near-infrared range.