Temperature-dependent thermal conductivities of 1D semiconducting nanowires via four-point-probe 3-ω method.
We report on a systematic study of the thermal transport characteristics of both as-grown zinc oxide and gallium nitride nanowires (NWs) via the four-point-probe 3-ω method in the temperature range 130-300 K. Both as-grown NWs were synthesized by a vapor-liquid-solid growth mechanism, and show clear n-type semiconducting behavior without any defects, which enables both the NWs to be promising candidates for thermoelectric materials. To measure the thermal conductivities of both NWs with lower heat loss and measurement errors, the suspended structures were formed by a combination of an e-beam lithography process and a random dispersion method. The measured thermal conductivities of both NWs are greatly reduced compared to their bulk materials due to the enhanced phonon scattering via the size effect and dopants (impurities). Furthermore, we observed that the Umklapp peaks of both NWs are shifted to a higher temperature than those of their bulk counterparts, indicating that phonon-boundary scattering dominates over other phonon scattering due to the size effect.
Department of Physics, National University of Singapore, Singapore 117542, Republic of Singapore.
Seung-Yong
SY
Lee
Mi-Ri
MR
Lee
No-Won
NW
Park
Gil-Sung
GS
Kim
Heon-Jin
HJ
Choi
Tae-Youl
TY
Choi
Sang-Kwon
SK
Lee
D004566:Electrodes; D004867:Equipment Design; D005708:Gallium / Q000737:chemistry; D036103:Nanotechnology; D053770:Nanowires / Q000737:chemistry*; D060739:Phonons; D012666:Semiconductors; D013696:Temperature; D015034:Zinc Oxide / Q000737:chemistry
C473348:gallium nitride; D005708:Gallium; D015034:Zinc Oxide