Study On The Heat Transfer Properties Of Black Phosphorene And Its Heterostructures

With the rapid update and iteration of flexible and intelligent electronic devices,the discovery of new semiconductor materials and the modulation of their performance have become very urgent.Two-dimensional materials have extremely broad application prospects in the new generation of semiconductor materials due to their large specific surface area,excellent electronic and mechanical properties.Among them,black phosphorene(BP)have received widespread attention due to its adjustable direct band gap,higher electron mobility and on-off ratio,and it has also made up for the lack of band gap of graphene as a semiconductor.In addition,BP has anisotropy in terms of heat transfer characteristics,mechanical characteristics,and optical properties,which will facilitate the discovery of its potential thermoelectric effects and other functions.Based on its electronic characteristics,BP has been used in the research of electronic devices such as field effect transistors,photoelectric detectors and converters,and thermoelectric equipment.Micro-interfaces and micro-boundary structures such as two-dimensional heterostructures are widely exist in these devices.As the size of the device becomes smaller and the degree of integration becomes even higher,the complex microstructure and abnormal heat transfer mechanism make the heat dissipation problem extremely challenging.Therefore,the study on the heat transfer characteristics of BP and its heterostructures is very necessary and has practical significance.This thesis focuses on the monolayer and bilayer BP structures,and systematically studies the influence mechanism of the edge topology and the BP heterostructure interface on the heat transfer.In this thesis,molecular dynamics and lattice dynamics methods are mainly used.First,the effects of three different edge structures on the thermal conductivity of bilayer BP nanoribbons are studied.The results show that phonons scatter significantly at the boundary of the klein edge BP structure,resulting in the lowest thermal conductivity.On the contrary,the U-shaped edge structure has the highest thermal stability.Secondly,the influence of the grain boundary on the thermal conductivity and thermal rectification characteristics of the monolayer BP was studied,and the study found that there is an obvious thermal resistance at the interface.The interface thermal resistance exhibits an obvious size effect.When the size difference between the two sides of the grain boundary is relevantly large,the thermal rectification coefficient of the structure can be as high as 270%.Finally,the van der Waals heterostructure of BP/Mo S2 was studied,and the mechanism affecting the heat transfer at the interface was explored,and it was found that there was no obvious anisotropy in the interface heat conduction.This study provides a theoretical basis for the thermal diffusion management of electronic devices based on BP,and also provides a reference for the possibility of BP and related two-dimensional materials in the application of phononic devices.