Author
S.G. Lyubchenko
Bio: S.G. Lyubchenko is an academic researcher from National Technical University. The author has contributed to research in topics: Hall effect & Seebeck coefficient. The author has an hindex of 6, co-authored 9 publications receiving 175 citations.
Papers
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TL;DR: In this paper, the authors attribute this oscillatory behavior to quantum-size effects, which are observable when the electron mean-free path and Fermi wave length exceed the film thickness d.
Abstract: Oscillatory thickness dependences of the electrical conductivity, Hall coefficient, charge carrier mobility, and Seebeck coefficient were obtained at room temperature for n-type thin Bi films (d=3–300 nm) fabricated by the thermal evaporation of a bismuth crystal in a vacuum and deposition on mica substrates at 380 K. We attribute this oscillatory behavior to quantum-size effects, which are observable when the electron mean-free path and Fermi wave length exceed the film thickness d.
62 citations
TL;DR: In this article, the dependence of the thermoelectric properties of n-PbTe, p-SnTe, and n-pbTe heterostructures on the SnTe quantum well width (dSnTe=0.5-6.0nm) at fixed PbTe barrier layers thicknesses were studied.
Abstract: The dependencies of the thermoelectric properties of n-PbTe∕p-SnTe∕n-PbTe heterostructures on the SnTe quantum well width (dSnTe=0.5–6.0nm) at fixed PbTe barrier layers thicknesses were studied. It was established that the thickness dependencies of the Seebeck coefficient, electrical conductivity, the Hall coefficient, charge carrier mobility, and the thermoelectric power factor are distinctly nonmonotonic. The observed effect is attributed to the size quantization of the energy spectrum of the hole gas in a SnTe quantum well.
56 citations
TL;DR: In this paper, it was shown that the gap between the valence and conduction bands in the semiconductor region increases with decreasing temperature, and it was suggested that in this thickness range a semimetal-semiconductor transition occurs.
25 citations
TL;DR: In this paper, the dependence of the elastic stress in a growing layer (either PbTe or SnTe) on the layer thickness and the critical thickness are in good agreement with those calculated theoretically.
24 citations
TL;DR: In this paper, the Hall coefficient RH and Seebeck coefficient S at room temperature on the thickness of thin PbTe films prepared by the thermal evaporation in vacuum of n-type pbTe crystals with various charge carrier concentrations (1017-1019 cm−3) and their deposition on mica substrates were obtained.
17 citations
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TL;DR: The field of thermoelectrics has long been recognized as a potentially transformative power generation technology and the field is now growing steadily due to their ability to convert heat directly into electricity and to develop cost effective, pollution-free forms of energy conversion.
632 citations
TL;DR: In this article, the authors focus on major novel strategies to achieve high-performance thermoelectric (TE) materials and their applications, and present a review of these strategies.
Abstract: Thermoelectric (TE) materials have the capability of converting heat into electricity, which can improve fuel efficiency, as well as providing robust alternative energy supply in multiple applications by collecting wasted heat, and therefore, assisting in finding new energy solutions. In order to construct high performance TE devices, superior TE materials have to be targeted via various strategies. The development of high performance TE devices can broaden the market of TE application and eventually boost the enthusiasm of TE material research. This review focuses on major novel strategies to achieve high-performance TE materials and their applications. Manipulating the carrier concentration and band structures of materials are effective in optimizing the electrical transport properties, while nanostructure engineering and defect engineering can greatly reduce the thermal conductivity approaching the amorphous limit. Currently, TE devices are utilized to generate power in remote missions, solar-thermal systems, implantable or/wearable devices, the automotive industry, and many other fields; they are also serving as temperature sensors and controllers or even gas sensors. The future tendency is to synergistically optimize and integrate all the effective factors to further improve the TE performance, so that highly efficient TE materials and devices can be more beneficial to daily lives.
563 citations
TL;DR: It is theoretically predicted that two-dimensional bismuth will show the quantum spin-Hall effect, both by calculating the helical edge states, and by showing the nontriviality of the Z2 topological number.
Abstract: We show that the spin-Hall conductivity in insulators is related to a magnetic susceptibility representing the strength of the spin-orbit coupling. We use this relationship as a guiding principle to search real materials showing quantum spin-Hall effect. As a result, we theoretically predict that two-dimensional bismuth will show the quantum spin-Hall effect, both by calculating the helical edge states, and by showing the nontriviality of the ${Z}_{2}$ topological number, and propose possible experiments.
525 citations
TL;DR: This review has attempted to survey and compare the recent work on colloidal synthesis, film and nanocrystal composite material fabrication, concentrating on narrow bandgap chalcogenide materials and some of their topical applications in the solar energy and biological fields.
Abstract: The chemistry, material processing and fundamental understanding of colloidal semiconductor nanocrystals (quantum dots) are advancing at an astounding rate, bringing the prospects of widespread commercialization of these novel and exciting materials ever closer. Interest in narrow bandgap nanocrystals in particular has intensified in recent years, and the results of research worldwide point to the realistic prospects of applications for these materials in solar cells, infrared optoelectronics (e.g. lasers, optical modulators, photodetectors and photoimaging devices), low cost/large format microelectronics, and in biological imaging and biosensor systems to name only some technologies. Improvements in fundamental understanding and material quality are built on a vast body of experience spread over many different methods of colloidal synthetic growth, each with their own strengths and weaknesses for different materials and sometimes with regard to particular applications. The nanocrystal growth expertise is matched by a rapidly expanding, and highly interdisciplinary, understanding of how best to assemble these materials into films or hybrid composites and thereby into useful devices, and again there are many different strategies that can be adopted. In this review we have attempted to survey and compare the recent work on colloidal synthesis, film and nanocrystal composite material fabrication, concentrating on narrow bandgap chalcogenide materials and some of their topical applications in the solar energy and biological fields. Since these applications are attracting rising interest across a wide range of disciplines, from the biological sciences, device engineering, and materials processing fields as well as the physics and synthetic chemistry communities, we have endeavoured to make the review of these narrow bandgap nanomaterials both comprehensive and accessible to newcomers to the area.
354 citations
TL;DR: In this article, the authors introduce the theory behind thermoelectric materials and details the predicted and demonstrated enhancements of ZT in nanoscale and nanostructured thermocomponent materials, including thin films and superlattices, nanowires and nanotubes.
Abstract: Thermoelectric materials can be used for solid state power generation and heating/cooling applications. The figure of merit of thermoelectric materials, ZT, which determines their efficiency in a thermoelectric device, remains low for most conventional bulk materials. Nanoscale and nanostructured thermoelectric materials are promising for increasing ZT relative to the bulk. This review introduces the theory behind thermoelectric materials and details the predicted and demonstrated enhancements of ZT in nanoscale and nanostructured thermoelectric materials. We discuss thin films and superlattices, nanowires and nanotubes, and nanocomposites, providing a ZT comparison among various families of nanocomposite materials. We provide some perspectives regarding the origin of enhanced ZT in nanoscale and nanostructured materials and suggest some promising and fruitful research directions for achieving high ZT materials for practical applications.
346 citations