The thermal boundary conductance of Al/SiO2, Al/Si, Au/SiO2, and Au/Si are measured by a femtosecond laser transient thermoreflectance technique. The distinct differences of the interfacial thermal conductance between...The thermal boundary conductance of Al/SiO2, Al/Si, Au/SiO2, and Au/Si are measured by a femtosecond laser transient thermoreflectance technique. The distinct differences of the interfacial thermal conductance between these samples are observed. For the same metal film, the thermal boundary conductance between metal and substrate decreases with the thermal conductivity of the substrate. The measured results are explained with the phonon diffusion mismatch model by introducing a phonon transmission coefficient across the interface.展开更多
The interface(IF) phonons of the wurtzite quantum cascade lasers(QCL) are investigated using the transfer-matrix method(TMM).The IF modes are presented in the longitudinal optical-phonon frequency for the Al0.2Ga0.8N/...The interface(IF) phonons of the wurtzite quantum cascade lasers(QCL) are investigated using the transfer-matrix method(TMM).The IF modes are presented in the longitudinal optical-phonon frequency for the Al0.2Ga0.8N/GaN and Al0.15Ga0.85N/GaN QCLs,and two IF modes can be changed into other modes if their wave numbers are less than the special values.Owing to the more dispersive properties of IF phonons with the increasing Al composition,the scattering rates in both QCLs increase with the Al composition.展开更多
基金supported by the National Basic Research Program of China ("973" Project) (Grant No. 2011CB707605)the National Nature Science Foundation of China (Grant Nos. 50875047, 50776017, 50925519, 51106029)
文摘The thermal boundary conductance of Al/SiO2, Al/Si, Au/SiO2, and Au/Si are measured by a femtosecond laser transient thermoreflectance technique. The distinct differences of the interfacial thermal conductance between these samples are observed. For the same metal film, the thermal boundary conductance between metal and substrate decreases with the thermal conductivity of the substrate. The measured results are explained with the phonon diffusion mismatch model by introducing a phonon transmission coefficient across the interface.
基金supported by the National Natural Science Foundation of China (No.50602018)the Cooperation Subject between Guangdong Province and Hong Kong (No. 2007A010501008)
文摘The interface(IF) phonons of the wurtzite quantum cascade lasers(QCL) are investigated using the transfer-matrix method(TMM).The IF modes are presented in the longitudinal optical-phonon frequency for the Al0.2Ga0.8N/GaN and Al0.15Ga0.85N/GaN QCLs,and two IF modes can be changed into other modes if their wave numbers are less than the special values.Owing to the more dispersive properties of IF phonons with the increasing Al composition,the scattering rates in both QCLs increase with the Al composition.