Energy Conversion Using New Thermoelectric Generator

During recent years, microelectronics helped to develop complex and varied technologies. It appears that many of these technologies can be applied successfully to realize Seebeck micro generators: photolithography and deposition methods allow to elaborate thin thermoelectric structures at the micro-scale level. Our goal is to scavenge energy by developing a miniature power source for operating electronic components. First Bi and Sb micro-devices on silicon glass substrate have been manufactured with an area of 1cm2 including more than one hundred junctions. Each step of process fabrication has been optimized: photolithography, deposition process, anneals conditions and metallic connections. Different device structures have been realized with different micro-line dimensions. Each devices performance will be reviewed and discussed in function of their design structure.Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions

Precise control of thermal conductivity at the nanoscale through individual phonon-scattering barriers

International audienceThe ability to precisely control the thermal conductivity (κ) of a material is fundamental in the development of on-chip heat management or energy conversion applications. Nanostructuring permits a marked reduction of κ of single-crystalline materials, as recently demonstrated for silicon nanowires. However, silicon-based nanostructured materials with extremely low κ are not limited to nanowires. By engineering a set of individual phonon-scattering nanodot barriers we have accurately tailored the thermal conductivity of a single-crystalline SiGe material in spatially defined regions as short as ∼15 nm. Single-barrier thermal resistances between 2 and 4×10−9 m2 K W−1 were attained, resulting in a room-temperature κ down to about 0.9 W m−1 K−1, in multilayered structures with as little as five barriers. Such low thermal conductivity is compatible with a totally diffuse mismatch model for the barriers, and it is well below the amorphous limit. The results are in agreement with atomistic Green’s function simulations

E-textile technology review - from materials to application

Wearable devices are ideal for personalized electronic applications in several domains such as healthcare, entertainment, sports and military. Although wearable technology is a growing market, current wearable devices are predominantly battery powered accessory devices, whose form factors also preclude them from utilizing the large area of the human body for spatiotemporal sensing or energy harvesting from body movements. E-textiles provide an opportunity to expand on current wearables to enable such applications via the larger surface area offered by garments, but consumer devices have been few and far between because of the inherent challenges in replicating traditional manufacturing technologies (that have enabled these wearable accessories) on textiles. Also, the powering of e-textile devices with battery energy like in wearable accessories, has proven incompatible with textile requirements for flexibility and washing. Although current e-textile research has shown advances in materials, new processing techniques, and one-off e-textile prototype devices, the pathway to industry scale commercialization is still uncertain. This paper reports the progress on the current technologies enabling the fabrication of e-textile devices and their power supplies including textile-based energy harvesters, energy storage mechanisms, and wireless power transfer solutions. It identifies factors that limit the adoption of current reported fabrication processes and devices in the industry for mass-market commercialization

Etude et développement de composants thermoélectriques à base de couches minces

Thermoelectrics is a science recently given to the style of the day, as power sources scavenging. From these perspectives, study and design of thin films thermoelectric modules are justified: actually these modules, with their low dimensions, about one centimetre square, can be integrated and used in many and varied fields such as car industry, human body environment, wireless sensors power supply... Thus realization and characterization of several modules have been carried out, with different materials and various geometries. For that, development of semimetallic and semiconductor thin films processes, respectively with bismuth/antimony and silicon/silicon-germanium, has been studied and optimized. Moreover use of nanostructured materials can increase thermoelectric performances, in particular via a decrease in thermal conductivity. Within this framework, a theoretical study of electrical and thermal transports in nanostructures has been lead. This study has been validated by experimental measurements realized on Si/SiGe superlattices, justifying their integration into thermoelectric devices.La thermoélectricité est une science remise au goût du jour depuis quelques années en tant que source de récupération d'énergie. Dans cette optique, l'étude et la conception de dispositifs thermoélectriques à base de films minces se justifient parfaitement : en effet, les faibles dimensions de ces modules, de l'ordre du cm2, permettent leur intégration et leur utilisation dans des domaines nombreux et variés, tels l'industrie automobile, l'environnement du corps humain, l'alimentation de capteurs sans fil... Ainsi, ces travaux ont permis la réalisation et la caractérisation de plusieurs modules, composés de matériaux de différente nature, et de diverses géométries. Pour cela, le développement des procédés de calibration de couches minces, à la fois de matériaux semimétalliques, en bismuth et antimoine, mais aussi de matériaux semiconducteurs, en silicium et silicium-germanium, a été étudié et optimisé. De plus, l'utilisation de matériaux nanostructurés permet une amélioration des performances thermoélectriques via notamment une diminution de la conductivité thermique. Dans ce cadre, une étude théorique sur les transports électriques et thermiques dans les nanostructures, complémentée de mesures expérimentales sur des superréseaux Si/SiGe, ont permis de valider ces propos et de justifier leur intégration au sein de dispositifs thermoélectriques

Etude et développement de composants thermoélectriques à base de couches minces

La thermoélectricité est une science remise au goût du jour depuis quelques années en tant que source de récupération d énergie. Dans cette optique, l étude et la conception de dispositifs thermoélectriques à base de films minces se justifient parfaitement : en effet, les faibles dimensions de ces modules, de l ordre du cm2, permettent leur intégration et leur utilisation dans des domaines nombreux et variés, tels l industrie automobile, l environnement du corps humain, l alimentation de capteurs sans fil Ainsi, ces travaux ont permis la réalisation et la caractérisation de plusieurs modules, composés de matériaux de différente nature, et de diverses géométries. Pour cela, le développement des procédés de calibration de couches minces, à la fois de matériaux semimétalliques, en bismuth et antimoine, mais aussi de matériaux semiconducteurs, en silicium et silicium-germanium, a été étudié et optimisé. De plus, l utilisation de matériaux nanostructurés permet une amélioration des performances thermoélectriques via notamment une diminution de la conductivité thermique. Dans ce cadre, une étude théorique sur les transports électriques et thermiques dans les nanostructures, complémentée de mesures expérimentales sur des superréseaux Si/SiGe, ont permis de valider ces propos et de justifier leur intégration au sein de dispositifs thermoélectriques.Thermoelectrics is a science recently given to the style of the day, as power sources scavenging. From these perspectives, study and design of thin films thermoelectric modules are justified: actually these modules, with their low dimensions, about one centimetre square, can be integrated and used in many and varied fields such as car industry, human body environment, wireless sensors power supply Thus realization and characterization of several modules have been carried out, with different materials and various geometries. For that, development of semimetallic and semiconductor thin films processes, respectively with bismuth/antimony and silicon/silicon-germanium, has been studied and optimized. Moreover use of nanostructured materials can increase thermoelectric performances, in particular via a decrease in thermal conductivity. Within this framework, a theoretical study of electrical and thermal transports in nanostructures has been lead. This study has been validated by experimental measurements realized on Si/SiGe superlattices, justifying their integration into thermoelectric devices.GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF

3D printing of bulk thermoelectric materials: laser powder bed fusion of N-type silicon germanium

International audienceAmong Additive Manufacturing (AM) methods, Laser Powder Bed Fusion (L-PBF), also called Selective Laser Melting (SLM), is prevalent to printing complex metal parts in small and medium series. Recent studies in L-PBF processing develops the manufacturing of new materials, including thermoelectric (TE) materials. This study presents manufacturing of an N type Si$_{80}$Ge$_{20}$ powder by L-PBF. Silicon germanium alloy is a TE material intended for high temperature applications. It is the first time that this semiconductor material is studied by AM technology. Dense samples of various shapes and sizes were produced, and a first process window was identified. Structural analyses have been performed, highlighting good densification. Unfortunately, mechanical cracking occurs in all samples. TE properties were investigated on as built samples, displaying low values (ZT = 0.11 at 600 °C), due to poor electrical conductivity. Overall, these results show that L-PBF of silicon germanium is possible, which could open up its scope of applications

Development of bulk thermoelectric N-type SiGe alloy by laser powder bed fusion

International audienceLike printing in its day, additive manufacturing has revolutionized current production methods in many areas like aeronautics, military or medicine. Among these methods, Laser Powder Bed Fusion (L-PBF) is prevalent to printing complex metal parts in small and medium series. Techniques developed recently in L-PBF pave the way for producing new types of materials via this method, including thermoelectric (TE) materials. This document presents the research work carried out at CEA to study the manufacturing of silicon-germanium alloy by L-PBF, a TE material intended for high temperature applications. In this study, we achieved successfully the printing of several dense samples, and then discuss their microstructures, chemical composition and thermoelectric properties

3D printing of bulk thermoelectric materials: laser powder bed fusion of N-type silicon germanium

International audienceAmong Additive Manufacturing (AM) methods, Laser Powder Bed Fusion (L-PBF), also called Selective Laser Melting (SLM), is prevalent to printing complex metal parts in small and medium series. Recent studies in L-PBF processing develops the manufacturing of new materials, including thermoelectric (TE) materials. This study presents manufacturing of an N type Si$_{80}$Ge$_{20}$ powder by L-PBF. Silicon germanium alloy is a TE material intended for high temperature applications. It is the first time that this semiconductor material is studied by AM technology. Dense samples of various shapes and sizes were produced, and a first process window was identified. Structural analyses have been performed, highlighting good densification. Unfortunately, mechanical cracking occurs in all samples. TE properties were investigated on as built samples, displaying low values (ZT = 0.11 at 600 °C), due to poor electrical conductivity. Overall, these results show that L-PBF of silicon germanium is possible, which could open up its scope of applications

Development of bulk thermoelectric N-type SiGe alloy by laser powder bed fusion

International audienceLike printing in its day, additive manufacturing has revolutionized current production methods in many areas like aeronautics, military or medicine. Among these methods, Laser Powder Bed Fusion (L-PBF) is prevalent to printing complex metal parts in small and medium series. Techniques developed recently in L-PBF pave the way for producing new types of materials via this method, including thermoelectric (TE) materials. This document presents the research work carried out at CEA to study the manufacturing of silicon-germanium alloy by L-PBF, a TE material intended for high temperature applications. In this study, we achieved successfully the printing of several dense samples, and then discuss their microstructures, chemical composition and thermoelectric properties

Device with deformable shell including an internal piezoelectric circuit

A device (10) including a deformable shell (12) delimiting an inner space (14), and: a resilient band (18, 30, 32) suspended in the inner space (14) and including two ends secured to the deformable shell (12), said band (18, 30, 32) including a piezoelectric material (30, 32) to generate an electric voltage under the effect of the deformation of the shell (12) and two electrodes for collecting the voltage; and an electronic circuit (34) for processing the voltage, arranged on the resilient band (18, 30, 32) and connected to the electrodes of the resilient band (18, 30, 32)