The Exploration On Chemical Vapor Synthesis And Photodetection Performance Of Two-Dimensional Ternary PbSnS₂

Two-dimensional materials have attracted wide attention from researchers due to their unique physical and chemical properties.They have shown broad application prospect in many fields such as optics,electronics,and topological physics.Compared with two-dimensional binary systems,the two-dimensional ternary system provides a new degree of freedom to adjust physical properties by introducing a third element.The introduction of new elements changes the crystal structure and local electronic structure of the material,which in turn changes the symmetry of the crystal structure of the material to make it have low symmetry anisotropy,etc.,and the change of the internal structure of the local electron leads to the wide absorption edge energy of the ternary system.However,the research of two-dimensional ternary system is still in its infancy,mainly limited by its controllable preparation,which seriously hinders its research in the field of electronics and optoelectronics.PbSnS₂ exhibits layered materials,p-type semiconductors,anisotropy,etc.,and has great potential in the field of optoelectronic devices.But controllable synthesis is the main factor limiting its application.Based on the above dilemma,this thesis focuses on the development of new two-dimensional ternary semiconductor PbSnS₂ and studies their photoelectric properties.The main research contents are as follows:?1?With the assisted of salt and molecular sieve,high-quality p-type two-dimensional ternary PbSnS₂ nanosheets were synthesized by chemical vapor deposition using Pb₃O₄,SnO,S powder as precursor and mica as substrate for collection.The theoretical results show that they have a strong anisotropic electron band structure.The angle-resolved polarized Raman spectroscopy demonstrates that the two-dimensional PbSnS₂ nanosheets exhibit strong in-plane anisotropic properties.?2?The photoelectric properties of device based on PbSnS₂ nanosheets was tested and we found that the device has a good photoresponse to the 532 nm laser.Angle-resolved electronic and optoelectronic tests show optoelectronic performance have strong in-plane anisotropy.The Zigzag direction shows higher responsivity than the Armchair direction(R_Zigzag=21.9 AW^-1,R_Armchair=17.5 AW^-1),higher external quantum efficiency.Mobility ratio in Armchair and Zigzag directions reached 1.78(?_Armchair/?_Zigzag?1.78).Further,The test of The PbSnS₂ nanosheets variable temperature electric transport was carried out.The test of variable temperature electrical transport found a weak Schottky barrier of 63.7 meV between the material and the electrode.