Thermal Conductivity Of Semiconductors Research Articles

High-Throughput Screening of Rattling-Induced Ultralow Lattice Thermal Conductivity in Semiconductors.

Thermoelectric (TE) materials with rattling model show ultralow lattice thermal conductivity for high-efficient energy conversion between heat and electricity. In this work, by analysis of the key spirit of the rattling model, we propose an efficient empirical descriptor to realize the high-throughput screening of ultralow thermal conductivity in a series of semiconductors. This descriptor extracts the structural information of rattling atoms whose bond lengths with all the nearest neighboring atoms are larger than the sum of corresponding covalent radiuses. We obtain 1171 candidates from the Materials Project (MP) Database that contains more than 100 000 materials. Combining the empirical equation of high-throughput computation with a machine learning algorithm, we compute the approximate lattice thermal conductivities (κL) and find the κL values of 532 materials are less than 2.0 W m-1 K-1 at 300 K, which can be regarded as the criteria of ultralow κL in general. In particular, we demonstrate that halide double perovskites structures show ultralow κL, which provides valuable references for promising low κL materials in future experiments. In order to further verify our computational results, we calculate accurate κL for Rb2SnBr6 and CsCu3O2 as candidates with the low lattice thermal conductivity by solving the phonon Boltzmann transport equation. In particular, we demonstrate that Rb2SnBr6 has the lowest κL value of 0.1 W m-1 K-1 at 300 K of all known thermal conductivity materials with the rattling model so far.

Lattice Thermal Transport in the Homogeneous Cage‐Like Compounds Cu3VSe4 and Cu3NbSe4: Interplay between Phonon‐Phase Space, Anharmonicity, and Atomic Mass

AbstractUnderstanding the correlation between crystal structure and thermal conductivity in semiconductors is very important for designing heat‐transport‐related devices, such as high‐performance thermoelectric materials and heat dissipation in micro‐nano‐scale devices. In this work, the lattice thermal conductivity ( ) of the cage‐like compounds Cu3VSe4 and Cu3NbSe4 was investigated by experimental measurements and first‐principles calculations. The experimental of Cu3NbSe4 is approximately 25 % lower than that of Cu3VSe4 at 300 K. The relevant important physical parameters, including the sound velocity, heat capacity, weighted phonon phase space (W), and third‐order force constants along with atomic mass were theoretically analyzed. It is found that W is the dominant parameter in determining the , and the other factors only play a minor role. The physical origin is the relatively “soft” lattice of Cu3NbSe4 with heavier atomic mass. This research provides deep insight into the correlation between the thermal conductivity and crystal structure and paves the way for discovering high‐performance thermal management device and thermoelectric materials with intrinsically low .

Thermal Ramp Type of Photo-Thermal Excitation in Hall Current and Variable Thermal Conductivity of Semiconductor Elastic Material

In this article, the variable thermal conductivity which it depending on temperature gradient in context of the photothermal excitation process of a semiconductor elastic material is studied. In the presence of Hall current effect the governing equations is introduced in one dimension subjected to thermal ramp type. The interaction between thermal-elastic-mechanical-plasma waves are used during the models of dual-phase-lag (DPL) and Lord-Shulman (LS) according to thermoelasticity theory. Laplace transform method in one dimension (1D) is used to get the solutions of physical fields quantities under investigation. The mechanical (which describe the case when the traction is free) and thermal ramp type at the free surface are applied through the photo-generated (recombination) transport processes due to the light energy absorption. The inversion of Laplace transform is used to observe the complete solution of physical quantities. The influence of Hall current, thermal memories with variable thermal conductivity are illustrated graphically and discussed on the resulting quantities.

The Effect of Electron-Phonon Interactions on Thermal Conductivity

Thermal conductivity (κ) is a key transport parameter in the fields of thermoelectric, heat management, and other functional materials research. For a long time, it is generally accepted that phonon-phonon interactions dominate the phonon thermal conductivity in semiconductors, which are the parent compounds of thermoelectric materials. Despite the well-known effect of electron-phonon interactions on the charge carrier mobility, the same on the thermal conductivity only starts to attract attention recently. In this work, we solved the Boltzmann transport equations for phonons considering both phonon-phonon interactions and electron-phonon interactions obtained from first principles calculations. It is demonstrated that electron-phonon interactions could also have a pronounced effect on the phonon transport properties, especially when the carrier concentration is large. A case study is given in Mg-based thermoelectric materials.

Effect of nano-film thickness on thermal resistance at water/silicon interface

Parallel to the developments in micro/nano manufacturing techniques, component sizes in micro/nano electro mechanical systems have been decreasing to nanometer scales. Decrease in lengths in heat transfer direction below the heat carrier phonon length scales reduces thermal conduction in semiconductors. This study shows that such altered phonon spectrums with the decrease of size also reduce the heat transfer at the solid/liquid interfaces and can be correlated with the thermal conductivity of the slab. Using Molecular Dynamics (MD), we measured heat transfer between water and silicon of different thickness between 5 nm and 60 nm. Silicon slabs exhibit a linear temperature profile through the bulk where thermal conductivities measured based on Fourier law decreased by the decreasing slab thickness. We applied a semi-theoretical formulism on variation of conductivity by slab thickness. At the interface of these slabs and water, heat passage is disturbed due to the phonon mismatch of dissimilar materials, which is mostly considered as solid/liquid couple interface properties by the earlier literature. Resistance for phonon passage characterized as Kapitza length (LK) is measured for different slab thicknesses at different surface wetting conditions varying between hydrophilic to hydrophobic. Increasing surface wetting decreases the LK while at a certain wetting, decreasing the slab thickness increases the LK. Once the LK of different size slabs normalized by its bulk value (assumed to be the LK of the thickest slab at the corresponding wetting), LK variation by silicon thickness shows a universal behavior independent of surface wetting. A mathematical model describing the exponential increase of LK by decreasing thickness was developed and validated by an earlier model. We further developed a correlation between the corresponding changes of LK and conductivity with respective to their bulk values by analytically combining two models as (LK/LK-Bulk)=exp3.94kBulk-k/(k×kBulk) , using which LK can be predicted from available thermal conductivities of a certain material. Results are crucial for thermal management of current and future electronics.

Thermal conductivity reduction by acoustic Mie resonance in nanoparticles

We evaluate the impact of acoustic Mie resonance in nanoparticles on the thermal conductivity of semiconductor and polymer composites. By appropriately choosing the bulk modulus and density, and selecting the size of the nanoparticle to align the Mie resonances with the dominant portion of the thermal conductivity spectrum, we show that large reductions in thermal conductivity are achievable with a dilute concentration of nanoparticles. This can be useful for enhancing ZT for thermoelectric applications, since a dilute loading of particles will minimally impact electrical conductivity. We apply the model to explain the steep reduction in thermal conductivity observed previously in semiconductor alloys and then show that acoustic Mie resonance in polysiloxane nanoparticles can be used to reduce the thermal conductivity of an amorphous polymer by nearly a factor of two.

Resonant phonon scattering in semiconductors

The origins of the dramatic effect of some dopants on the thermal conductivity of semiconductors are studied. By analyzing the cases of B-doped 3C-SiC, B-doped diamond, N-doped diamond and a simple linear chain model, small symmetry breaking structural distortions and a high density of states are identified as the key ingredients in resonant phonon scattering.

Conductivity-limiting bipolar thermal conductivity in semiconductors.

Intriguing experimental results raised the question about the fundamental mechanisms governing the electron-hole coupling induced bipolar thermal conduction in semiconductors. Our combined theoretical analysis and experimental measurements show that in semiconductors bipolar thermal transport is in general a “conductivity-limiting” phenomenon, and it is thus controlled by the carrier mobility ratio and by the minority carrier partial electrical conductivity for the intrinsic and extrinsic cases, respectively. Our numerical method quantifies the role of electronic band structure and carrier scattering mechanisms. We have successfully demonstrated bipolar thermal conductivity reduction in doped semiconductors via electronic band structure modulation and/or preferential minority carrier scatterings. We expect this study to be beneficial to the current interests in optimizing thermoelectric properties of narrow gap semiconductors.

History of Agrophysics: The Creative Activity of A. F. Chudnovsky

A. F. Chudnovsky was a prominent agrophysicist and a pioneer in the heat physics of soil. His primary research interests were thermo-physics of soils, thermo-physical properties of dispersed materials, the thermal conductivity of semiconductors, engineering and physical aspects of thermal soil melioration, and energy and mass transfer in the soil-plant-air system. He also conducted research on physical and technical methods (electronics) in agrophysics, remote sensing of agricultural fields, and agrophysical basics of crop programming. Among these areas of agrophysics, he completed 20 scientific monographs. A. F. Chudnovsky was a talented scholar, a great mentor, and under his leadership, more than 50 Masters of Science and 20 Doctoral Theses were completed. This paper is written to commemorate Dr. A. F. Chudnovsky’s dedicated contributions to agrophysical research and development.

Thermal conductivity in higher-order generalized hydrodynamics: Characterization of nanowires of silicon and gallium nitride

An analysis of the influence of geometry and size on the thermal conductivity in semiconductors, particularized to the study in Si and GaN, is presented. This is done in the framework of a higher-order generalized hydrodynamics (HOGH) of phonons in semiconductors, driven away from equilibrium by external sources. This HOGH is derived by the method of moments from a generalized Peierls–Boltzmann kinetic equation built in the framework of a Non-Equilibrium Statistical Ensemble Formalism. We consider the case of wires (cylindrical geometry) exploring the effect of size (radius), particularly in the nanometric scale when comparison with experiment is done. Maxwell times, which are quite relevant to define the hydrodynamic movement, are evidenced and characterized.

Vibrational Dynamics of Impurities in Semiconductors: Phonon Trapping and Isotope Effects

Optical tools such as infra-red absorption, photoluminescence, or Raman spectroscopy have been used for decades to observe the localized vibrational modes associated with impurities in semiconductors. The frequencies of these modes slightly shift with the isotope of the impurity while host-atom isotopes often show up as shoulders in the spectra. These shifts and shoulders are precious indicators of the nature of the defect. But sometimes, very small isotope-related frequency shifts cause very large changes in vibrational lifetimes. Impurity-isotope effects have now been predicted to impact the thermal conductivity of semiconductors containing a few atomic percent of impurities. Impurity isotope effects can be surprisingly large.

Non-equilibrium dynamics for impurities in semiconductors

Abstract This paper summarizes the ‘first-principles’ calculations of the vibrational properties of impurities, which are critical to the optical identification of defects. The issue of temperature control for non-equilibrium molecular dynamics (NEMD) is discussed. Applications of NEMD include the calculations of the temperature-dependence of vibrational lifetimes and of the thermal conductivity of semiconductors as a function of their impurity content.

Phonon transport in silicon, influence of the dispersion properties choice on the description of the anharmonic resistive mechanisms

Thermal conductivity in semiconductors is investigated through the phonon transport description. From the former studies based on the gas kinetic theory to the recent ones using the Monte Carlo methods or the radiative multifux models, each technique involves the dispersion properties of the crystal lattice. Besides, most of these studies have been done in the frame of the relaxation time approximation of collision processes. In this study, the importance of the choice of the dispersion curves and time relaxation parameters are pointed out. A complete description of the transverse umklapp interaction is provided without any adjustment parameters. New insights of the energy conservation surface calculation, involved in phonon-phonon time relaxation expression, are provided. Using simple and more complex models, we have determined the heat transport properties, in the temperature range from 50 K to 1000 K in bulk silicon. We especially focused our attention on the thermal conductivity as a function of the phonon anharmonic resistive mechanisms for two models of dispersion: “linear” and “quadratic”. We demonstrate that very different thermal conductivity properties can be calculated according to the chosen description of lattice vibrations.

Thermal Transport in Gallium Nitride Materials and Heterostructures

Gallium nitride (GaN) and its heterostructures have been proposed for high-power electronic and optoelectronic device applications. Accurate knowledge of the thermal conductivity of these materials and understanding of the underlying mechanism for thermal transport are important for the thermal performance simulations of GaN-based devices. This review focuses on the theoretical modeling of phonon thermal transport in GaN materials and heterostructures. It begins with a review of the experimental observations of the thermal conductivity of GaN and their discrepancy with the early theoretical predictions. This is followed by a detailed discussion of a recent theoretical model for heat conduction in GaN films, which considers explicitly both intrinsic and extrinsic phonon scattering processes important for GaN. The effects of dislocations and impurities are analyzed. Theoretical modeling of the thermal conductivity of low-dimensional GaN materials, such as nanoscale AIN/GaN/AIN heterostructures, is presented next. Modification of phonon dispersion due to acoustic mismatch across the interior interfaces is taken into account. Its influence on phonon group velocity and density of states is discussed. The possibility of improving thermal conduction in semiconductors through phonon engineering is also addressed. Also presented here is the recent experimental observation of the thermal conductivity of GaN nanowires and its comparison with the theoretical models.

Three-phonon phase space and lattice thermal conductivity in semiconductors

We present calculations of the phase space for three-phonon scattering events in severalgroup IV, III–V and II–VI semiconductors employing an adiabatic bond charge model toaccurately represent the phonon dispersions. We demonstrate that this phase space variesinversely with the measured lattice thermal conductivities of these materials overa wide range of temperatures where three-phonon scattering is the dominantmechanism for scattering phonons. We find that this qualitative relationship isrobust in spite of variations in material parameters between the semiconductors.Anomalous behavior occurs in three III–V materials that have large mass differencesbetween constituent elements, which we explain in terms of the severely restrictedthree-phonon phase space arising from the large gap between acoustic and optic phononbranches.

An Apparatus for Measuring the High-Temperature Thermal Conductivity of Semiconductors and Their Melts

An installation for investigating the thermal conductivity of semiconductors and their melts over a wide temperature range (300–1100 K) is described. In contrast to the devices used earlier for this purpose, the thermal conductivity was measured in a hermetically sealed autoclave filled after evacuation with spectroscopically pure argon to prevent the oxidation, evaporation, and decomposition of the substance under study. The error of thermal-conductivity measurements did not exceed 8% at 1000 K.

Thermal conduction in semiconductors. By C. M. Rhandari and D. M. Rowe. John Wiley + Sons Ltd., Chichester 1988. xix, 224 pp., bound, £ 19.15. ‐ ISBN 0‐470‐21049‐4

Advanced MaterialsVolume 2, Issue 10 p. 507-507 Book Review Thermal conduction in semiconductors. By C. M. Rhandari and D. M. Rowe. John Wiley + Sons Ltd., Chichester 1988. xix, 224 pp., bound, £ 19.15. - ISBN 0-470-21049-4 Peter Türkes, Peter Türkes Siemens AG, ZFE ME FKS 41 Postfach 83 09 53, D-8000 München 83 (FRG)Search for more papers by this author Peter Türkes, Peter Türkes Siemens AG, ZFE ME FKS 41 Postfach 83 09 53, D-8000 München 83 (FRG)Search for more papers by this author First published: October 1990 https://doi.org/10.1002/adma.19900021018AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume2, Issue10October 1990Pages 507-507 RelatedInformation

Estimated thermal diffusivity, Prandtl number and Grashof number of molten GaAs, InP, and GaSb

We have determined the thermal diffusivity, Prandtl number and Grashof number of molten GaAs, InP, and GaSb, all necessary parameters in coupled fluid flow and heat transfer modeling of crystal growth. Among the primary quantities there is reliable experimental data for the density as a function of temperature for each liquid which then permits the derivation of the volume expansion coefficient. Since the experimental data for the viscosity of the compounds are a complicated though monotomic function of temperature, we have performed a least-square analysis (log viscosity versus 1/ T) including only results relevant in the vicinity of the melting points ( T f). Lacking measurements for the thermal conductivity, K L, of molten GaAs and InP, we introduce a novel scaling technique. An exhaustive survey of the literature on the thermal conductivity of semiconductors and subsequent analysis has led to the discovery that the ratio K L/ K S for the liquid and solid phases at T f is nearly constant for Si, Ge, InSb, and GaSb, ranging between 2.13 and 2.93. Thus we could approximate K L for GaAs and InP from K S at T f by employing an average multiplying factor of 2.5. Combination of the assembled properties yields for the thermal diffusivity (cm 2/s), Prandtl number, and Grashof number of GaAs the values 0.072, 0.068, and 2.9 × 10 7, respectively. Likewise, the recommended values for InP are 0.103, 0.015, and 6.2 × 10 8, and for GaSb ar 0.087, 0.044, and 2.4 × 10 7. Finally, the implications of these estimates with regard to fluid flow and heat transfer simulations of Czochralski growth are discussed.

The thermal conductivity of semiconductors of the system As2(Se1−xTex)3 depending on temperature and pressure

The thermal conductivity of the compounds As2Se3 and As2Te3 and solid solutions on their base are investigated in solid and liquid states for crystalline and glassy modifications depending on composition, temperature and hydrostatic pressure. The temperature and concentration dependences of thermal conductivity of polycrystalline samples can be explained by the influence of U-processes, N-processes, and point defects on thermal resistance of lattice. Anomaly of temperature course of the thermal conductivity in softening range and increase of the thermal conductivity at hydrostatic pressure up 3.5 kbar can be explained by the change of elastic parameters of the lattice and phonon velocity. [Russian Text Ignored].

Lattice thermal conductivity of semiconductors: A chemical bond approach

Lattice thermal conductivity of semiconductors: A chemical bond approach