Applied Physics Letters · 2014 · 51 citations · 23 references
EngineeringMaterials EngineeringMaterials ScienceCondensed Matter PhysicsHeat TransferSemiconductor MaterialsSemiconductor PhysicsThermal Properties Of MaterialsThermal Properties Of SemiconductorsThermoelectric MaterialsWide Band Gap SemiconductorsWide-bandgap SemiconductorsGallium NitrideGallium Nitride (Gan) MaterialsIn-plane Thermal TransportPolarizationSuperlattice ThermoelectricsThermal ConductivityThermoelectric PropertiesTwo-dimensional Electron Gases
A novel polarization field engineering based strategy to simultaneously achieve high electrical conductivity and low thermal conductivity in thermoelectric materials is demonstrated. Polarization based electric fields are used to confine electrons into two-dimensional electron gases in GaN/AlN/Al0.2Ga0.8N superlattices, resulting in improved electron mobilities as high as 1176 cm2/Vs and in-plane thermal conductivity as low as 8.9 W/mK. The resulting room temperature ZT values reach 0.08, a factor of four higher than InGaN and twelve higher than GaN, demonstrating the potential benefits of this polarization based engineering strategy for improving the ZT and efficiencies of thermoelectric materials.
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Convergence of electronic bands for high performance bulk thermoelectrics
Yanzhong Pei, Xiaoya Shi, Aaron D. LaLonde et al. · Nature · 2011 · 4.2K citations