Artificially Atomic-scale Ordered Superlattice Alloys for Thermoelectric Applications

Abstract

ABSTRACTWe report artificially atomic-scale ordered superlattice alloy systems, new scheme to pursue high-ZT materials. We have fabricated Bi/Sb superlattice alloys that are artificially ordered on the atomic scale using MBE, confirmed by the presence of XRD superlattice satellites. We have observed that the electronic structure can be modified from semimetal, through zero-gap, to semiconductor by changing the superlattice period and sublayer thicknesses using electrical resistivity, thermopower, and magneto-transport measurements. InSb/Bi superlattice alloys have also been prepared and studied using XRD and thermopower measurements, which shows that their thermoelectric transport properties can be modified in accordance with structural modification. This superlattice alloy scheme gives us one more tool to control and tune the electronic structure and consequently the thermoelectric properties.