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We report a wafer scale approach for the fabrication of 400 element power generator modules composed of 200 n-type ErAs:(InGaAs)0.8(InAlAs)0.2 and 200 p-type ErAs:InGaAs alloy thermoelectric elements. The thermoelectric properties of the materials were characterized. Two sets of generator modules with the element thicknesses of 20 and 10 μm, respectively, were fabricated. The 20 μm module had an output power density of 2.5 W/cm2 and 3.5 V open circuit voltages, and the 10 μm generator modules had an output power density of 1.12 W/cm2 and open circuit voltage of 2.1 V. The performance of thermoelectric generator modules can further be improved by increasing the thicknesses of the elements and reducing the electrical and thermal parasitic resistances. [ABSTRACT FROM AUTHOR]

We report a wafer scale approach for the fabrication of thin-film power generators composed of arrays of 400 p and n type ErAs:InGaAs/InGaAlAs superlattice thermoelectric elements. The elements incorporate ErAs metallic nanoparticles into the semiconductor superlattice structure to provide charge carriers and create scattering centers for phonons. p- and n-type ErAs:InGaAs/InGaAlAs superlattices with a total thickness of 5 μm were grown on InP substrate using molecular beam epitaxy. The cross-plane Seebeck coefficients and cross-plane thermal conductivity of the superlattice were measured using test pattern devices and the 3ω method, respectively. Four hundred element power generators were fabricated from these 5 μm thick, 200 μm×200 μm in area superlattice elements. The output power was over 0.7 mW for an external resistor of 100 Ω with a 30 K temperature difference drop across the generator. We discuss the limitations to the generator performance and provide suggestions for improvements. [ABSTRACT FROM AUTHOR]

The magneto-transport properties of Bi2Se3–ySy were investigated. Magnetoresistance (MR) decreases with an increase in the S content, and finally, for 7% (i.e., y = 0.21) S doping, the magnetoresistance becomes negative. This negative MR is unusual as it is observed when a magnetic field is applied in the perpendicular direction to the plane of the sample. The magneto-transport behavior shows the Shubnikov–de Haas (SdH) oscillation, indicating the coexistence of surface and bulk states. The negative MR has been attributed to the non-trivial bulk conduction. [ABSTRACT FROM AUTHOR]