title: Surface Chemical Tuning of Phonon and Electron Transport in Free-Standing Silicon Nanowire Arrays.
abstract: We report electronic and phononic transport measurements of monocrystalline batch-fabricated silicon nanowire (SiNW) arrays functionalized with different surface chemistries. We find that hydrogen-terminated SiNWs prepared by vapor HF etching of native-oxide-covered devices show increased electrical conductivity but decreased thermal conductivity. We used the kinetic Monte Carlo method to solve the Boltzmann transport equation and also numerically examine the effect of phonon boundary scattering. Surface transfer doping of the SiNWs by cobaltocene or decamethylcobaltocene drastically improves the electrical conductivity by 2 to 4 orders of magnitude without affecting the thermal conductivity. The results showcase surface chemical control of nanomaterials as a potent pathway that can complement device miniaturization efforts in the quest for more efficient thermoelectric materials and devices.
authors: Laboratory of Thermodynamics in Emerging Technologies, Department of Mechanical and Process Engineering, ETH Zürich , Sonneggstrasse 3, 8092 Zürich, Switzerland.
authors: Ying
authors: Y
authors: Pan
authors: Laboratory for Solid State Physics, Department of Physics, ETH Zürich , Otto-Stern-Weg 1, 8093 Zürich, Switzerland.
authors: Ye
authors: Y
authors: Tao
authors: Institute of Mineral Engineering, Division of Materials Science and Engineering, RWTH Aachen University , Mauerstrasse 5, 52064 Aachen, Germany.
authors: Guangzhao
authors: G
authors: Qin
authors: Institute of Electromagnetic Fields, Department of Information Technology and Electrical Engineering, ETH Zürich , Gloriastrasse 35, 8092 Zürich, Switzerland.
authors: Yuriy
authors: Y
authors: Fedoryshyn
authors: Laboratory of Thermodynamics in Emerging Technologies, Department of Mechanical and Process Engineering, ETH Zürich , Sonneggstrasse 3, 8092 Zürich, Switzerland.
authors: Shyamprasad N
authors: SN
authors: Raja
authors: Institute of Mineral Engineering, Division of Materials Science and Engineering, RWTH Aachen University , Mauerstrasse 5, 52064 Aachen, Germany.|Aachen Institute for Advanced Study in Computational Engineering Science (AICES), RWTH Aachen University , Mauerstrasse 5, 52062 Aachen, Germany.
authors: Ming
authors: M
authors: Hu
authors: Laboratory for Solid State Physics, Department of Physics, ETH Zürich , Otto-Stern-Weg 1, 8093 Zürich, Switzerland.
authors: Christian L
authors: CL
authors: Degen
authors: Laboratory of Thermodynamics in Emerging Technologies, Department of Mechanical and Process Engineering, ETH Zürich , Sonneggstrasse 3, 8092 Zürich, Switzerland.
authors: Dimos
authors: D
authors: Poulikakos
keywords: Silicon nanowires; electron and phonon transport; surface transfer doping