A combined conduction and radiation heat transfer model was used to simulate the heat transfer within wafer and investigate the effect of thermal transport properties on temperature non-uniformity within wafer surface...A combined conduction and radiation heat transfer model was used to simulate the heat transfer within wafer and investigate the effect of thermal transport properties on temperature non-uniformity within wafer surface. It is found that the increased conductivities in both doped and undoped regions help reduce the temperature difference across the wafer surface. However, the doped layer conductivity has little effect on the overall temperature distribution and difference. The temperature level and difference on the top surface drop suddenly when absorption coefficient changes from 104 to 103 m-1. When the absorption coefficient is less or equal to 103 m-1, the temperature level and difference do not change much. The emissivity has the dominant effect on the top surface temperature level and difference. Higher surface emissivity can easily increase the temperature level of the wafer surface. After using the improved property data, the overall temperature level reduces by about 200 K from the basis case. The results will help improve the current understanding of the energy transport in the rapid thermal processing and the wafer temperature monitor and control level.展开更多
Beyond graphene, the layered transition metal dichalcogenides （TMDs） have gained considerable attention due to their unique properties. Herein, we review the lattice dynamic and thermal properties of monolayer TMDs,...Beyond graphene, the layered transition metal dichalcogenides （TMDs） have gained considerable attention due to their unique properties. Herein, we review the lattice dynamic and thermal properties of monolayer TMDs, including their phonon dispersion, relaxation time, mean free path （MFP）, and thermal conductivities. In particular, the experimental and theoretical studies reveal that the TMDs have relatively low thermal conductivities due to the short phonon group velocity and MFP, which poses a significant challenge for efficient thermal management of TMDs-based devices. Importantly, recent studies have shown that this issue could be largely addressed by connecting TMDs and other materials （such as metal electrode and graphene） with chemical bonds, and a relatively high interracial thermal conductance （ITC） could be achieved at the covalent bonded interface. The ITC of MoS2/Au interface with chemical edge contact is more than 10 times higher than that with physical side contact. In this article, we review recent advances in the study of TMD-related ITC. The effects of temperature, interfacial vacancy, contact orientation, and phonon modes on the edge-contacted interface are briefly discussed.展开更多
Thermal conductivity of nanowires(NWs)is a crucial criterion to assess the operating performance of NWs-based device applications,such as in the field of heat dissipation,thermal management,and thermoelectrics.Therefo...Thermal conductivity of nanowires(NWs)is a crucial criterion to assess the operating performance of NWs-based device applications,such as in the field of heat dissipation,thermal management,and thermoelectrics.Therefore,numerous research interests have been focused on controlling and manipulating thermal conductivity of one-dimensional materials in the past decade.In this review,we summarize the state-of-the-art research status on thermal conductivity of NWs from both experimental and theoretical studies.Various NWs are included,such as Si,Ge,Bi,Ti,Cu,Ag,Bi2Te3,ZnO,AgTe,and their hybrids.First,several important size effects on thermal conductivity of NWs are discussed,such as the length,diameter,orientation,and cross-section.Then,we introduce diverse nanostructuring pathways to control the phonons and thermal transport in NWs,such as alloy,superlattices,core-shell structure,porous structure,resonant structure,and kinked structure.Distinct thermal transport behaviors and the associated underlying physical mechanisms are presented.Finally,we outline the important potential applications of NWs in the fields of thermoelectrics and thermal management,and provide an outlook.展开更多
Numerical solutions of three-dimensional, incompressible and unsteady Navier-Stokes equations for constant diameter swirling pipe flows are used to study vortex breakdown, including the detailed flow structures in the...Numerical solutions of three-dimensional, incompressible and unsteady Navier-Stokes equations for constant diameter swirling pipe flows are used to study vortex breakdown, including the detailed flow structures in the bubble domain and the ＂tail＂ behind the bubble during the vortex breakdown, and a comparison is made between the numerical solutions and the experimental results.展开更多
With the size reduction of nanoscale electronic devices, the heat generated by the unit area in integrated circuits will be increasing exponentially, and consequently the thermal management in these devices is a very ...With the size reduction of nanoscale electronic devices, the heat generated by the unit area in integrated circuits will be increasing exponentially, and consequently the thermal management in these devices is a very important issue. In addition, the heat generated by the electronic devices mostly diffuses to the air in the form of waste heat, which makes the thermoelectric energy conversion also an important issue for nowadays. In recent years, the thermal transport properties in nanoscale systems have attracted increasing attention in both experiments and theoretical calculations. In this review, we will discuss various theoretical simulation methods for investigating thermal transport properties and take a glance at several interesting thermal transport phenomena in nanoscale systems. Our emphasizes will lie on the advantage and limitation of calculational method, and the application of nanoscale thermal transport and thermoelectric property.展开更多
基金Project(N110204015)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(2012M510075)supported by the China Postdoctoral Science Foundation
文摘A combined conduction and radiation heat transfer model was used to simulate the heat transfer within wafer and investigate the effect of thermal transport properties on temperature non-uniformity within wafer surface. It is found that the increased conductivities in both doped and undoped regions help reduce the temperature difference across the wafer surface. However, the doped layer conductivity has little effect on the overall temperature distribution and difference. The temperature level and difference on the top surface drop suddenly when absorption coefficient changes from 104 to 103 m-1. When the absorption coefficient is less or equal to 103 m-1, the temperature level and difference do not change much. The emissivity has the dominant effect on the top surface temperature level and difference. Higher surface emissivity can easily increase the temperature level of the wafer surface. After using the improved property data, the overall temperature level reduces by about 200 K from the basis case. The results will help improve the current understanding of the energy transport in the rapid thermal processing and the wafer temperature monitor and control level.
基金financial support by the Agency for Science, Technology and Research (A*STAR), Singaporethe use of computing resources at the A*STAR Computational Resource Centre, Singaporesupported in part by the Science and Engineering Research Council (152-70-00017)
文摘Beyond graphene, the layered transition metal dichalcogenides （TMDs） have gained considerable attention due to their unique properties. Herein, we review the lattice dynamic and thermal properties of monolayer TMDs, including their phonon dispersion, relaxation time, mean free path （MFP）, and thermal conductivities. In particular, the experimental and theoretical studies reveal that the TMDs have relatively low thermal conductivities due to the short phonon group velocity and MFP, which poses a significant challenge for efficient thermal management of TMDs-based devices. Importantly, recent studies have shown that this issue could be largely addressed by connecting TMDs and other materials （such as metal electrode and graphene） with chemical bonds, and a relatively high interracial thermal conductance （ITC） could be achieved at the covalent bonded interface. The ITC of MoS2/Au interface with chemical edge contact is more than 10 times higher than that with physical side contact. In this article, we review recent advances in the study of TMD-related ITC. The effects of temperature, interfacial vacancy, contact orientation, and phonon modes on the edge-contacted interface are briefly discussed.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFB0406000)the National Natural Science Foundation of China(Grant Nos.51506153 and 11334007)+1 种基金the Science and Technology Commission of Shanghai Municipality,China(Grant No.17ZR1448000)the National Youth 1000 Talents Program in China and the Startup Grant at Tongji University,China
文摘Thermal conductivity of nanowires(NWs)is a crucial criterion to assess the operating performance of NWs-based device applications,such as in the field of heat dissipation,thermal management,and thermoelectrics.Therefore,numerous research interests have been focused on controlling and manipulating thermal conductivity of one-dimensional materials in the past decade.In this review,we summarize the state-of-the-art research status on thermal conductivity of NWs from both experimental and theoretical studies.Various NWs are included,such as Si,Ge,Bi,Ti,Cu,Ag,Bi2Te3,ZnO,AgTe,and their hybrids.First,several important size effects on thermal conductivity of NWs are discussed,such as the length,diameter,orientation,and cross-section.Then,we introduce diverse nanostructuring pathways to control the phonons and thermal transport in NWs,such as alloy,superlattices,core-shell structure,porous structure,resonant structure,and kinked structure.Distinct thermal transport behaviors and the associated underlying physical mechanisms are presented.Finally,we outline the important potential applications of NWs in the fields of thermoelectrics and thermal management,and provide an outlook.
基金supported by the National Basic Research Program of China (973 Program, Grant No. 2008CB418203)
文摘Numerical solutions of three-dimensional, incompressible and unsteady Navier-Stokes equations for constant diameter swirling pipe flows are used to study vortex breakdown, including the detailed flow structures in the bubble domain and the ＂tail＂ behind the bubble during the vortex breakdown, and a comparison is made between the numerical solutions and the experimental results.
基金Project supported by the Nation Key Research and Development Program of China(Grant No.2017YFB0701602)the National Natural Science Foundation of China(Grant No.11674092)
文摘With the size reduction of nanoscale electronic devices, the heat generated by the unit area in integrated circuits will be increasing exponentially, and consequently the thermal management in these devices is a very important issue. In addition, the heat generated by the electronic devices mostly diffuses to the air in the form of waste heat, which makes the thermoelectric energy conversion also an important issue for nowadays. In recent years, the thermal transport properties in nanoscale systems have attracted increasing attention in both experiments and theoretical calculations. In this review, we will discuss various theoretical simulation methods for investigating thermal transport properties and take a glance at several interesting thermal transport phenomena in nanoscale systems. Our emphasizes will lie on the advantage and limitation of calculational method, and the application of nanoscale thermal transport and thermoelectric property.
