Anisotropy of the Thermal Conductivity in GaAs/AlAs Superlattices

作者：Luckyanova Maria N; Johnson Jeremy A; Maznev A A; Garg Jivtesh; Jandl Adam; Bulsara Mayank T; Fitzgerald Eugene A; Nelson Keith A; Chen Gang^*

来源：Nano Letters, 2013, 13(9): 3973-3977.

DOI：10.1021/nl4001162

• Nanoscale heat conduction
• superlattice
• thermal conductivity anisotropy
• time-domain thermoreflectance
• transient thermal grating

We combine the transient thermal grating and time-domain thermoreflectance techniques to characterize the anisotropic thermal conductivities of GaAs/AlAs superlattices from the same wafer. The transient grating technique is sensitive only to the in-plane thermal conductivity, while time-domain thermoreflectance is sensitive to the thermal conductivity in the cross-plane direction, making them a powerful combination to address the challenges associated with characterizing anisotropic heat conduction in thin films. We compare the experimental results from the GaAs/AlAs superlattices with first-principles calculations and previous measurements of Si/Ge SLs. The measured anisotropy is smaller than that of Si/Ge SLs, consistent with both the mass-mismatch picture of interface scattering and with the results of calculations from density-functional perturbation theory with interface mixing included.

• 出版日期2013-9
• 单位MIT