Using nonequilibrium molecular dynamics simulations and nonequilibrium Green's function method, we investigate the thermoelectric properties of a series of zigzag and chiral carbon nanotubes which exhibit interesting diameter and chirality dependence. Our calculated results indicate that these carbon nanotubes could have higher ZT values at appropriate carrier concentration and operating temper...

A rapid hot press system in which the heat is supplied by RF induction to rapidly consolidate thermoelectric materials is described. Use of RF induction heating enables rapid heating and consolidation of powdered materials over a wide temperature range. Such rapid consolidation in nanomaterials is typically performed by spark plasma sintering (SPS) which can be much more expensive. Details of t...

Heat transport in the quantum Hall regime is investigated using micron-scale heaters and thermometers positioned along the edge of a millimeter-scale two dimensional electron system (2DES). The heaters rely on localized current injection into the 2DES, while the thermometers are based on the thermoelectric effect. In the nu=1 integer quantized Hall state, a thermoelectric signal appears at an e...

An unusual thermoelectric response was observed in n-type perovskite oxide La1-xCexCoO3. Combining transport and magnetic measurements, we found that the thermoelectric response is driven by the spin-state transition of Co3+. This transition destroys the spin blockade effect and induces an abrupt decrease of resistivity as well as an insulator-metal transition. In contrast to the resistivity ch...

The optimization of the thermal co-evaporation deposition process for n-type bismuth telluride (Bi2Te3) thin films onto polyimide substrates for thermoelectric applications is reported. The influence of deposition parameters (evaporation rate and substrate temperature) on film composition and thermoelectric properties was studied for optimal thermoelectric performance. Energy-dispersive X-ray s...

Bi2Te3-based alloys have been intensively used for thermoelectric coolers and generators due to their high Seebeck coefficient S. So far, efforts to improve the S have been made mostly on changing the structures and components. Herein, we demonstrate an anomalous thermoelectricity in strained Bi2Te3 films, i.e., the value of S is obviously changed after reversing the direction of temperature gr...

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The apparatus for evaluation of the figure of merit (ZT) of thermoelectric devices has been developed. ZT value is comprised of three physical quantities, Seebeck coefficient, electrical conductivity, and thermal conductivity. However, to date, the ZT values of the thermoelectric devices have been evaluated by Harman method due to difficulty in measuring thermal conductivity of the devices with...

Thermoelectric materials are sometimes prepared using a sintering process in which the achievement of a high density is often one of the objectives. However, it has recently been shown that the introduction of a highly porous material is desirable in synthetic transverse thermoelements. Porosity may also be an advantage in conventional longitudinal thermoelectric modules in which a high thermal...

A portable thermal chamber with a volume of only 2.5 l capable of reaching temperatures over the −5C to 70C range was designed and constructed. In order to make the thermal chamber lightweight and portable, two series connected thermoelectric modules were used as actuators since their size and performance characteristics allow the portability and precise temperature control. The PID control pro...