Enhancement of Thermoelectric Efficiency by Uniaxial Tensile Stress in n-type GaAs Nanowires

Abhijeet Paul, Network for Computational Nanotechnology, Purdue University
Kai Miao, Network for Computational Nanotechnology, Purdue University
Ganesh Hegde, Network for Computational Nanotechnology, Purdue University
Saumitra Hehrotra, Network for Computational Nanotechnology, Purdue University
Mathieu Luisier, Network for Computational Nanotechnology, Purdue University
Gerhard Klimeck, Network for Computational Nanotechnology, Purdue University

Abstract

The thermoelectric power-factor (PF) and efficiency (ZT) of GaAs nanowires (NWs) can be improved by (i) choosing a proper wire growth and channel orientation, (ii) by applying uniaxial tensile stress, and (iii) suitable wire cross-section size. In this work we study the impact of these three factors on the PF and the ZT. Tensile stress, channel direction and cross-section size allows bandstructure engineering to tune the electronic conductance (G) and the Seebeck coefficient (S). [110] GaAs NWs grown on (111) surface provide maximum PF (3X) and ZT (1.3X) compared to [100]/(100) NWs, which can be attributed to the G enhancement induced by the L valley contribution under strain.

Discipline(s)

Engineering | Nanoscience and Nanotechnology