Quantum Modeling of Thermoelectric Properties of Si/Ge/Si Superlattices

Bulusu, Anuradha; Walker, D. G.

doi:10.1109/ted.2007.910574

Cited by 17 publications

(4 citation statements)

References 33 publications

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“…The quantum effects, such as electron confinement and tunneling, can be readily accounted through the modification of the DOS. The predictions given by the simple BTE-based methods have been in a good agreement with those by those sophisticated modern approaches, such as nonequilibrium Green's function (NEGF) methods, in which the results are obtained by directly solving the Schrodinger equation [196,197].…”

Section: Boltzmann Transport Equationsupporting

confidence: 63%

Waste Thermal Energy Harvesting (I): Thermoelectric Effect

Kong

Hng

et al. 2014

Waste Energy Harvesting

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Waste thermal energy (heat) is the second type of energy to be discussed. Usually, it is generated in a process by way of fuel combustion or chemical reaction, and then ''dumped'' into the environment even though it could still be reused for some useful and economic purpose. The essential quality of heat is not the amount but rather its ''value.'' The strategy of how to recover this heat depends in part on the temperature of the waste heat gases and the economics involved.Waste thermal energy is one of the largest sources of inexpensive, clean, and fuel-free energy available. The vast amount of heat that is discharged into the atmosphere everyday is one of the best sources of clean, fuel-free, and inexpensive energy. According to the US Department of Energy (DOE), up to 50 % of all fuels burned in the US goes unused into the atmosphere as waste heat is released to the atmosphere. Research indicates that the energy currently wasted by the industrial facilities in the U.S. could produce as much as 20 % of the total US electrical output with the associated 20 % reduction in greenhouse gas emissions. Various sources that can be classified as waste thermal energy (heat) with their properties are listed in Tables 4.1 , 4.2, 4.3, and 4.4 [1].Among the large quantities of waste heat that have been directly discharged into the Earth's environment, much of it is at temperatures which are too low to recover by using the conventional electrical power generators. Thermoelectric power generation, also known as thermoelectricity, has been demonstrated as a promising technology in the direct conversion of low-grade thermal energy, such as waste heat energy into electrical power. Probably, the earliest application is the utilization of waste heat from a kerosene lamp to provide thermoelectric energy to power a wireless device. Thermoelectric generators have also been used to provide small amounts electricity to remote regions, for instance, Northern Sweden, as an L. B. Kong et al., Waste Energy Harvesting, Lecture Notes in Energy 24,

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Section: Boltzmann Transport Equationsupporting

confidence: 63%

Waste Thermal Energy Harvesting (I): Thermoelectric Effect

Kong

Hng

et al. 2014

Waste Energy Harvesting

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“…Strain-induced energy splitting in Si/Ge/Si superlattices is shown to improve power factor by four orders in magnitude [192]. However, the gains in TE performance expected in such structures was shown to be limited by the reduction in conductivity of superlattices with thin barriers [193]. Quantum wire superlattices with lateral confine-ment were also studied with NEGF, while including the scattering processes due to electron-phonon couplings, phonon anharmonicity, charged impurities, surface and interface roughness and alloy disorder [194].…”

Section: Non-equilibrium Green's Functionsmentioning

confidence: 99%

Electronic Transport and Thermopower in 2D and 3D Heterostructures—A Theory Perspective

2019

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The impact of interfaces and heterojuctions on the electronic and thermoelectric transport properties of materials is discussed herein. Recent progress in understanding electronic transport in heterostructures of 2D materials ranging from graphene to transition metal dichalcogenides, their homojunctions (grain boundaries), lateral heterojunctions (such as graphene/MoS 2 lateral interfaces), and vertical van der Waals heterostructures is reviewed. Work on thermopower in 2D heterojunctions, as well as their applications in creating devices such as resonant tunneling diodes (RTDs), is also discussed. Last, the focus turns to work in 3D heterostructures. While transport in 3D heterostructures has been researched for several decades, here recent progress in theory and simulation of quantum effects on transport via the Wigner and non-equilibrium Green's functions approaches is reviewed. These simulation techniques have been successfully applied toward understanding the impact of heterojunctions on transport properties and thermopower, which finds applications in energy harvesting, and electron resonant tunneling, with applications in RTDs. In conclusion, tremendous progress has been made in both simulation and experiments toward the goal of understanding transport in heterostructures and this progress will soon be parlayed into improved energy converters and quantum nanoelectronic devices.

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“…Nanolaminates or superlattices that consist of alternating thin films without porous defects are attractive and promising, especially because of their good mechanical characteristics. Periodic nanolaminates or superlattice nanowires such as Si/Ge, − Ge/SiGe, Si/SiGe, − GaAs/AlAs, − Bi 2 Te 3 /Sb 2 Te 3, − W/Al 2 O 3 , Ta/TaO x , Ge 2 Sb 2 Te 5 /ZnS:SiO 2 , Mo/Si, and Au/Si have been proposed; in some cases, they have been demonstrated to have a thermal conductivity perpendicular to the multilayers that is even lower than that of homogeneous amorphous structure and the theoretical predicted values. As the distances between interfaces decrease, the reduction effect on thermal conductivity increases .…”

Section: Introductionmentioning

confidence: 96%

Electrically Conductive Thermally Insulating Bi–Si Nanocomposites by Interface Design for Thermal Management

Sasaki

Goto

et al. 2018

ACS Appl. Nano Mater.

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We demonstrate, both by experiments and by data informatics, an alternative strategy to achieve ultralow thermal conductivity in a dense solid. The interfacial thermal resistance (ITR) prediction of the machine learning model is implemented in a nanoscale field. The size dependence on ITR is considered and applied to the interface design of nanostructuring. The Bi/Si system was selected from 2025 kinds of interfaces through the interface thermal resistance prediction model by machine learning. The BiSi nanocomposite, which was composed of crystallized Bi and amorphous Si, was designed with various parameters by a laboratory-built combinatorial sputtering system. Electrically conductive, thermally insulating BiSi nanocomposites were reported for the first time and have a thermal conductivity as low as 0.16 W m −1 K −1 . The ultralow thermal conductivity is attributed to the high ratio between the interfacial surface area and the volume because of the small Bi particle size and high Si/Bi atomic ratio. By introducing the informatics method, the potential candidates can be discovered and realized for thermoelectric applications.

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Quantum Modeling of Thermoelectric Properties of Si/Ge/Si Superlattices

Cited by 17 publications

References 33 publications

Waste Thermal Energy Harvesting (I): Thermoelectric Effect

Waste Thermal Energy Harvesting (I): Thermoelectric Effect

Electronic Transport and Thermopower in 2D and 3D Heterostructures—A Theory Perspective

Electrically Conductive Thermally Insulating Bi–Si Nanocomposites by Interface Design for Thermal Management

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