A study on photothermal waves in an unbounded semiconductor medium with cylindrical cavity
TL;DR: In this paper, the theory of coupled plasma, thermal, and elastic waves was used to investigate the wave propagation on semiconductor material with cylindrical cavity during photo-thermoelastic process.
Abstract: The theory of coupled plasma, thermal, and elastic waves was used to investigate the wave propagation on semiconductor material with cylindrical cavity during photo-thermoelastic process. An unbounded material, elastic semiconductor containing a cylindrical cavity with isotropic and homogeneous thermal and elastic properties has been considered. The inner surface of cavity is constrained, and the carrier density is photogenerated by an exponentially decaying pulse boundary heat flux. The eigenvalue approach, together with Laplace transform techniques, was used to obtain the analytical solutions. Numerical computations have been done for a silicon-like semiconductor material, and the results are presented graphically to estimate the effect of the coupling between the plasma, thermal, and elastic waves. The graphical results indicate that the thermal activation coupling parameter is an important phenomenon and has a great effect on the distribution of field quantities.
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TL;DR: In this article, the effect of variable thermal conductivity, which depend on temperature in the context of Photothermal diffusion (PTD), was studied and the complete solutions in time domain were observed by using a numerical approximation method.
Abstract: In this problem, we study the effect of variable thermal conductivity, which depend on temperature in the context of Photothermal diffusion (PTD). The PTD process is applied with thermoelasticity theory in chemical action. The model introduced describes the interaction between elastic-thermal-plasma waves, which based on the material properties of semiconductor elastic medium. The Laplace transform is used to solve the governing equations in one dimension of a thin circular plate. Some new constant will be appearing during the theoretical discussion. The mechanical forces and thermal loads are applied on the free surface of semiconductor to obtain the physical fields. The complete solutions in time domain are observed by using a numerical approximation method. The physical fields with some comparsions are presented analytically and graphically.
97 citations
TL;DR: In this paper, coupled plasma, thermal and elastic waves within an orthotropic infinite semiconducting medium in context of photothermal transport process having a spherica spore was studied.
Abstract: This article highlights on the study of coupled plasma, thermal and elastic waves within an orthotropic infinite semiconducting medium in context of photothermal transport process having a spherica...
92 citations
TL;DR: In this article, a mathematical model under the effect of Thomson heating of a semi-infinite semiconductor elastic medium is expressed and the charge density of induced electric current is expressed for a time functionally only.
Abstract: In this article, the novel mathematical model under the effect of Thomson heating of a semi-infinite semiconductor elastic medium is expressed. The thermoelasticity theory is applied in the presence of magnetic field when the medium illuminated by a laser pulse in context of photothermal excitation. The discussions are focused on studying the overlapping between plasma, thermal, electro-magnetic and elastic waves when they propagated in the medium. The two dimensional (2D) deformations is used in the governing equations when the medium is homogenous and isotropic. The charge density of induced electric current is expressed for a time functionally only. The physical fields are obtained when use the normal mode technique with some thermal, mechanical and plasma loads occur at the free surface of elastic semi-infinite semiconductor medium. The numerical calculations of physical field's distributions are discussed and shown graphically under the effect of Thomson parameter.
78 citations
TL;DR: In this paper, a model of two-dimensional deformations for two-temperature theory at the free surface under the excitation of thermoelastic wave by pulsed laser for a semi-infinite semiconducting medium is studied.
Abstract: A novel model of two-dimensional deformations for two-temperature theory at the free surface under the excitation of thermoelastic wave by pulsed laser for a semi-infinite semiconducting medium is studied. The effect of mechanical force during a photothermal process is investigated. The mathematical methods of the Lord–Shulman (LS includes one relaxation time) and Green–Lindsay (GL with two relaxation times) theories as well as the classical dynamical coupled theory (CD) are used. An exact expression for displacement components, force stresses, carrier density and distribution of temperature are obtained using the harmonic wave analysis. Combinations of two-temperature and photothermal theories are obtained analytically. Comparisons of the results are made between the three theories also. The effects of thermoelectric coupling parameter, two-temperature parameter on the displacement component, force stress, carrier density, and distribution of temperature for silicon (Si) medium have been illustrated graphically. The variations of the considered variables with the horizontal distance have been discussed.
77 citations
TL;DR: The effect of the initial magnetic field is introduced in the problem governing equations with the two-temperature theory and the complete solution in one dimension is obtained using Laplace transform technique.
Abstract: This article focuses on studying the dependence of the thermal conductivity of a semiconducting medium on temperature in context of photothermal transport process and variable thermal conductivity, chosen to be linear function in temperature. The effect of the initial magnetic field is introduced in the problem governing equations with the two-temperature theory. The complete solution in one dimension is obtained using Laplace transform technique. The thermal heating ramp type and mechanical load throughout the elastic-photothermal excitation are considered in the problem boundary conditions. Some physical fields are obtained by using numerical inversion of the Laplace transform and Riemann-sum approximation method. The thermo-dynamical temperature, conductive temperature, displacement, strain, normal stress and carrier density are discussed and shown graphically with some comparisons.
70 citations
Cites methods from "A study on photothermal waves in an..."
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17 Nov 2014
TL;DR: In this paper, a dual-phase-leg model is proposed to describe the heat transfer in solids with micro-structures, and experimental evidence supports the lagging behaviour in heat transport under various circumstances, including the high-order effect of phase legs in the delayed response.
Abstract: This work introduces a new concept in heat transfer, developing a transient model describing the fast-transient process of heat transport in solids with micro-structures. In describing the microstructural interaction effect in the short-term response, it extends the "macroscopic" concept that practisings engineers are already familiar with. The dual-phase-leg model covers the existing macroscopic and microscopic models in the same framework, including the classical diffusion model employing the Fourier's law and the thermal wave model for dielectric films, insulators, and semi-conductors, and the photon-electron interaction model for metals (microscopic). Chapters cover the current status of microscale heat transfer, the lagging behaviour in the transient response, experimental evidence supporting the lagging behaviour in heat transport under various circumstances, the high-order effect of phase legs in the delayed response, and the possible effect of lagging responses in the related fields of elasticity and forced convention.
1,122 citations
TL;DR: In this paper, the effect of thermal radiation on magnetohydrodynamics nanofluid flow between two horizontal rotating plates is studied and the significant effects of Brownian motion and thermophoresis have been included in the model of Nanofluide.
700 citations
TL;DR: In this article, the authors extended the theory of photoacoustic effect to include the contribution of mechanical vibration of the sample and solved equations for thermal and acoustic waves in both sample and gas.
Abstract: The theory of the photoacoustic effect is extended to include the contribution of mechanical vibration of the sample. Coupled equations for thermal and acoustic waves are solved in both sample and gas. It is shown that the pressure signal in the gas may be significantly affected by acoustic coupling in the sample, and experimental confirmation of this extended theory is given. The results of the fully coupled treatment are shown to be accurately reproduced by an extension of the Rosencwaig piston model: the pistonlike motion of the gas boundary layer adjoining the sample is superimposed on the mechanical vibration of the sample surface to give a composite piston displacement which then produces the pressure signal in the gas. The composite‐piston model provides relatively simple algebraic results applicable to many cases of physical interest.
451 citations
TL;DR: In this article, the theory of piezoelectric photoacoustic spectroscopy for condensed-matter samples is developed for condensedmatter samples, treating the sample as an elastic layer and neglecting the transducers effect on the sample, the three-dimensional uncoupled quasistatic thermoelastic equations are solved using a Green's function for the stress.
Abstract: The theory of piezoelectric photoacoustic spectroscopy is developed for condensed‐matter samples. Treating the sample as an elastic layer and neglecting the transducer’s effect on the sample, the three‐dimensional uncoupled quasistatic thermoelastic equations are solved using a Green’s function for the stress. An expression for the dependence of the signal on absorption, modulation frequency, thermal properties, and mechanical properties of the sample is derived. The theoretical predictions are experimentally verified, the sources of noise are analyzed, and the noise equivalent power is estimated. Finally, considerations for detector optimization are discussed.
296 citations
TL;DR: In this article, a method and apparatus for thin film thickness measurements with thermal waves in which heating and detection laser beams are focused onto the film, normal to the surface of the film with the two beams parallel and non-coaxial.
Abstract: A method and apparatus for thin film thickness measurements with thermal waves in which heating and detection laser beams are focused onto the film, normal to the surface of the film, with the two beams parallel and non-coaxial.
189 citations