Influence of Focusing on Phonon Propagation and Thermal Conductivity in Single Crystal Films with Different Types of Anisotropy of Elastic Energy

2018 ◽  
Vol 60 (5) ◽  
pp. 870-876 ◽  
Author(s):  
I. I. Kuleev
2001 ◽  
Vol 124 (2) ◽  
pp. 223-241 ◽  
Author(s):  
David G. Cahill ◽  
Kenneth Goodson ◽  
Arunava Majumdar

We review recent advances in experimental methods for high spatial-resolution and high time-resolution thermometry, and the application of these and related methods for measurements of thermal transport in low-dimensional structures. Scanning thermal microscopy (SThM) achieves lateral resolutions of 50 nm and a measurement bandwidth of 100 kHz; SThM has been used to characterize differences in energy dissipation in single-wall and multi-wall carbon nanotubes. Picosecond thermoreflectance enables ultrahigh time-resolution in thermal diffusion experiments and characterization of heat flow across interfaces between materials; the thermal conductance G of interfaces between dissimilar materials spans a relatively small range, 20<G<200 MW m−2K−1 near room temperature. Scanning thermoreflectance microscopy provides nanosecond time resolution and submicron lateral resolution needed for studies of heat transfer in microelectronic, optoelectronic and micromechanical systems. A fully-micromachined solid immersion lens has been demonstrated and achieves thermal-radiation imaging with lateral resolution at far below the diffraction limit, <2 μm. Microfabricated metal bridges using electrical resistance thermometry and joule heating give precise data for thermal conductivity of single crystal films, multilayer thin films, epitaxial superlattices, polycrystalline films, and interlayer dielectrics. The room temperature thermal conductivity of single crystal films of Si is strongly reduced for layer thickness below 100 nm. The through-thickness thermal conductivity of Si-Ge and GaAs-AlAs superlattices has recently been shown to be smaller than the conductivity of the corresponding alloy. The 3ω method has been recently extended to measurements of anisotropic conduction in polyimide and superlattices. Data for carbon nanotubes measured using micromachined and suspended heaters and thermometers indicate a conductivity near room temperature greater than diamond.


Author(s):  
L. E. Murr ◽  
G. Wong

Palladium single-crystal films have been prepared by Matthews in ultra-high vacuum by evaporation onto (001) NaCl substrates cleaved in-situ, and maintained at ∼ 350° C. Murr has also produced large-grained and single-crystal Pd films by high-rate evaporation onto (001) NaCl air-cleaved substrates at 350°C. In the present work, very large (∼ 3cm2), continuous single-crystal films of Pd have been prepared by flash evaporation onto air-cleaved (001) NaCl substrates at temperatures at or below 250°C. Evaporation rates estimated to be ≧ 2000 Å/sec, were obtained by effectively short-circuiting 1 mil tungsten evaporation boats in a self-regulating system which maintained an optimum load current of approximately 90 amperes; corresponding to a current density through the boat of ∼ 4 × 104 amperes/cm2.


2001 ◽  
Vol 27 (6) ◽  
pp. 451-453 ◽  
Author(s):  
S. S. Kucherenko ◽  
V. P. Pashchenko ◽  
P. I. Polyakov ◽  
S. I. Khartsev ◽  
V. A. Shtaba

1993 ◽  
Vol 73 (11) ◽  
pp. 7969-7971 ◽  
Author(s):  
Qixin Guo ◽  
Osamu Kato ◽  
Akira Yoshida

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