scholarly journals Study on the Cross Plane Thermal Transport of Polycrystalline Molybdenum Nanofilms by Applying Picosecond Laser Transient Thermoreflectance Method

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Tingting Miao ◽  
Weigang Ma ◽  
Xing Zhang ◽  
Keisuke Kubo ◽  
Masamichi Kohno ◽  
...  
Keyword(s):  
Thermal Diffusivity ◽  
Thermal Transport ◽  
Picosecond Laser ◽  
Free Electrons ◽  
Optical Components ◽  
Glass Substrates ◽  
The Cross ◽  
Significant Size ◽  
Different Thickness ◽  
Polycrystalline Molybdenum

Thin metal films are widely used as interconnecting wires and coatings in electronic devices and optical components. Reliable thermophysical properties of the films are required from the viewpoint of thermal management. The cross plane thermal transport of four polycrystalline molybdenum nanofilms with different thickness deposited on glass substrates has been studied by applying the picosecond laser transient thermoreflectance technique. The measurement is performed by applying both front pump-front probe and rear pump-front probe configurations with high quality signal. The determined cross plane thermal diffusivity of the Mo films greatly decreases compared to the corresponding bulk value and tends to increase as films become thicker, exhibiting significant size effect. The main mechanism responsible for the thermal diffusivity decrease of the present polycrystalline Mo nanofilms is the grain boundary scattering on the free electrons. Comparing the cross plane thermal diffusivity and inplane electrical conductivity indicates the anisotropy of the transport properties of the Mo films.

Thickness Dependent Structural and Optical Properties of Cadmium Selenide Thin Films

2013 ◽  
Vol 665 ◽  
pp. 159-167
Author(s):  
M.S. Jani ◽  
H.S. Patel ◽  
J.R. Rathod ◽  
K.D. Patel ◽  
V.M. Pathak ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Hexagonal Wurtzite Structure ◽  
Optical Bandgap ◽  
Bandgap Energy ◽  
Structural And Optical Properties ◽  
Structural Investigations ◽  
Glass Substrates ◽  
Optical Bandgap Energy ◽  
Different Thickness

In this paper structural and optical properties of CdSe thin films with different thickness deposited by thermal evaporation under vacuum onto glass substrates are presented. The structural investigations performed by means of XRD technique showed that the films have a polycrystalline and hexagonal (würtzite) structure. The values of some important parameters of the studied films (absorption coefficient and optical bandgap energy) are determined from transmission spectra. The values of the optical bandgap energy (Eg) calculated from the absorption spectra, ranged between 1.67 - 1.74 eV.

scholarly journals Comparative study of thermal transport in Zea mays straw and Zea mays heartwood (cork) boards

2010 ◽  
Vol 14 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Sunday Etuk ◽  
Louis Akpabio ◽  
Ita Akpan
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Zea Mays ◽  
Thermal Diffusivity ◽  
Comparative Study ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Thermal Transport ◽  
Insulation Material ◽  
Thermal Absorptivity

Thermal conductivity values at the temperature of 301-303K have been measured for Zea mays straw board as well as Zea mays heartwood (cork) board. Comparative study of the thermal conductivity values of the boards reveal that Zea mays heartwood board has a lower thermal conductivity value to that of the straw board. The study also shows that the straw board is denser than the heartwood board. Specific heat capacity value is less in value for the heartwood board than the straw board. These parameters also affect the thermal diffusivity as well as thermal absorptivity values for the two types of boards. The result favours the two boards as thermal insulators for thermal envelop but with heartwood board as a preferred insulation material than the straw board.

scholarly journals Intercalated ion tuning of the cross-plane thermal transport properties of graphite

AIP Advances ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 095225
Author(s):  
Wenjing Ju ◽  
Chongming Zhu ◽  
Zhiyong Wei
Keyword(s):  
Transport Properties ◽  
Thermal Transport ◽  
Thermal Transport Properties ◽  
The Cross

Stresses in Films Deposited by Planar Magnetron Sputtering on Glass Substrates of Different Thickness

1988 ◽  
Vol 130 ◽  
Author(s):  
Zhi-Feng Zhou ◽  
Yu-Dian Fan
Keyword(s):  
Magnetron Sputtering ◽  
Magnetic Characteristics ◽  
Substrate Thickness ◽  
Back Side ◽  
Structure And Properties ◽  
Capacitance Change ◽  
Glass Substrates ◽  
Thin Film Thermocouple ◽  
Planar Magnetron ◽  
Different Thickness

AbstractStresses affect the structure and properties of the films significantly. In this paper, Co-Cr films were deposited by D.C. planar magnetron sputtering on rectangular glass plates of thickness varied from 0.18 to 2.00mam. The measurement of stress was performed by the bending plate technique with the detection of capacitance change. The temperature of the bending plate was measured by an Fe-Ni thin film thermocouple on the back side of the substrate. The experimental results showed that the stresses were all tensile, but in the films on the thicker substrates were smaller than that on the thinner ones. And apparently the temperature rise of the thicker substrates during deposition was lower than that of the thinner ones. The magnetic characteristics of the Co-Cr films related to the substrate thickness may be attributed to both stress and temperature difference in the films deposited on the substrates of different thickness.

Experiment and Theoretical Study on Thermal Transport Process in Nano-Sized Copper Film

2013 ◽  
Vol 756-759 ◽  
pp. 108-111
Author(s):  
Fan Da Zeng ◽  
Ya Ping Han ◽  
Jin Xin Wang ◽  
Shao Ze Wang
Keyword(s):  
Thin Film ◽  
Finite Difference Method ◽  
Thermal Transport ◽  
Transport Process ◽  
Theoretical Study ◽  
Copper Film ◽  
Transport Processes ◽  
Time Resolved ◽  
Copper Thin Film ◽  
Glass Substrates

nanosized copper thin film was prepared on glass substrates by magnetron sputtering. 800 nm pump and 400nm probe technique were used to measure time-resolved reflectivity of copper thin film, and the heat transport processes of copper film were experimentally studied. Thermal transport processes in the copper film were numerically simulated by using Parabolic Two-Step (PTS) model with Finite Difference method. The result of the PTS model can well evaluate the measure date.

Superlattice Analysis for Tailored Thermal Transport Characteristics

2006 ◽  
Author(s):  
E. S. Landry ◽  
A. J. H. McGaughey ◽  
M. I. Hussein
Keyword(s):  
Thermal Conductivity ◽  
Thermal Transport ◽  
Direct Method ◽  
Continuum Theory ◽  
Lennard Jones ◽  
Constituent Species ◽  
The Cross ◽  
Dynamics Simulations ◽  
Superlattice Period

Molecular dynamics simulations and the Green-Kubo method are used to predict the thermal conductivity of binary Lennard-Jones superlattices and alloys. The superlattice thermal conductivity trends are in agreement with those obtained through the direct method, verifying that the Green-Kubo method can be used to examine thermal transport in heterostructures. The simulation temperature and the constituent species are fixed while the superlattice period structure is varied with the goals of (i) minimizing the cross-plane thermal conductivity and (ii) maximizing the ratio of in-plane to cross-plane thermal conductivities. The superlattice thermal conductivity in both the cross-plane and in-plane directions is found to be greater than the corresponding alloy value and less than the value predicted from continuum theory. The anisotropy of the thermal conductivity tensor is found to be at a maximum for a superlattice with a uniform layer thickness. Lattice dynamics calculations are used to investigate the role of optical phonons in the thermal transport.

Sub-picosecond laser induced damage test facility for petawatt reflective optical components characterizations

2015 ◽  
Author(s):  
Martin Sozet ◽  
Jérôme Néauport ◽  
Eric Lavastre ◽  
Nadja Roquin ◽  
Laurent Gallais ◽  
...  
Keyword(s):  
Picosecond Laser ◽  
Test Facility ◽  
Optical Components ◽  
Laser Induced Damage

Microscratch Analysis of The Adhesion Failure on Oxide Thin Films With Different Thickness

1996 ◽  
Vol 436 ◽  
Author(s):  
C. R. Ottermann ◽  
K. Bange ◽  
A. Braband ◽  
H. Haefke ◽  
W. Gutmannsbauer
Keyword(s):  
Thin Films ◽  
Chemical Vapour ◽  
Soda Lime ◽  
Fused Silica ◽  
Soda Lime Glass ◽  
Test Results ◽  
Glass Substrates ◽  
Adhesion Failure ◽  
Different Thickness ◽  
Deposition Techniques

AbstractAdhesion failures of Ti2 and Ta2O5 thin films deposited by reactive evaporation (RE), reactive ion plating (IP) and plasma impulse chemical vapour deposition (PICVD) on fused silica, AF 45, TEMPAX and soda-lime glass substrates are investigated by means of a micro-scratch tester. The oxide films possess thickness between 60 and 500 nm and show different mass densities depending on the deposition conditions. Scratch testing exhibits well pronounced detachment for thicker films on hard substrates. The clearance of the scratch signal is reduced with decreasing layer thickness or for softer substrate materials. The test results are also influenced by the various substrates and different chemical and mechanical properties of the films due to the alternate deposition techniques.

Manufacture of Lasers with Multiple Operating Modes

2012 ◽  
Vol 482-484 ◽  
pp. 1937-1940
Author(s):  
Chang Jun Zhu ◽  
Bing Xue ◽  
Xue Jun Zhai ◽  
Jun Fang He
Keyword(s):  
Phase Modulation ◽  
Velocity Dispersion ◽  
Group Velocity Dispersion ◽  
Picosecond Laser ◽  
Laser Pulses ◽  
Mode Locking ◽  
Pulse Mode ◽  
Operating Modes ◽  
Picosecond Laser Pulses ◽  
The Cross

A two-beam pumped Ti:sapphire laser with femtosecond and picosecond cavities was manufactured. Three operating modes, independent self mode-locking, cross mode-locking and multi-pulse operating, were achieved. In the independent self mode-locking mode, femtosecond and picosecond laser pulses were generated in the two cavities, respectively. In the cross mode-locking mode, synchronized femtosecond and picosecond laser pulses were obtained in the two cavities. In the multi-pulse mode, multi-pulses were produced in the picosecond cavity. The results show that, the independent self mode-locking mode is dominated mainly by group velocity dispersion and self-phase modulation, the cross mode-locking mode is governed primarily by cross-phase modulation and the multi-pulse operating is ruled largely by self-amplitude modulation.

scholarly journals Experimental Validation of Formula for Calculation Thermal Diffusivity in Superlattices Performed Using a Combination of Two Frequency-Domain Methods: Photothermal Infrared Radiometry and Thermoreflectance

2021 ◽  
Vol 11 (13) ◽  
pp. 6125
Author(s):  
Michał Pawlak ◽  
Timo Kruck ◽  
Nikolai Spitzer ◽  
Dariusz Dziczek ◽  
Arne Ludwig ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Thermal Diffusivity ◽  
Thermal Transport ◽  
Theoretical Formula ◽  
Elastic Continuum ◽  
Frequency Domain Methods ◽  
Different Temperatures ◽  
Infrared Radiometry

In this paper, we validate two theoretical formula used to characterize thermal transport of superlattices at different temperatures. These formulas are used to measure cross-plane thermal conductivity and thermal boundary resistance, when it is not possible to obtain heat capacity or thermal diffusivity and in-plane thermal conductivity. We find that the most common formula for calculating thermal diffusivity and heat capacity (and density) can be used in a temperature range of −50 °C to 50 °C. This confirms that the heat capacity in the very thin silicon membranes is the same as in bulk silicon, as was preliminary investigated using an elastic continuum model. Based on the obtained thermal parameters, we can fully characterize the sample using a new procedure for characterization of the in-plane and cross-plane thermal transport properties of thin-layer and superlattice semiconductor samples.

Sign in / Sign up

Export Citation Format

Share Document