Carrier dynamics in Si nanowires fabricated by metal-assisted chemical etching.
Silicon nanowire arrays fabricated by metal-assisted wet chemical etching have emerged as a promising architecture for solar energy harvesting applications. Here we investigate the dynamics and transport properties of photoexcited carriers in nanowires derived from an intrinsic silicon wafer using the terahertz (THz) time-domain spectroscopy. Both the dynamics and the pump fluence dependence of the photoinduced complex conductivity spectra up to several THz were measured. The photoinduced conductivity spectra follow a Lorentz dependence, arising from surface plasmon resonances in nanowires. The carrier lifetime was observed to approach 0.7 ns, which is limited primarily by surface trapping. The intrinsic carrier mobility was found to be ~1000 cm(2)/(V · s). Compared to other silicon nanostructures, these relative high values observed for both the carrier lifetime and mobility are the consequences of high crystallinity and surface quality of the nanowires fabricated by the metal-assisted wet chemical etching method.
Center of Super-Diamond and Advanced Films and Department of Physics and Materials Science, City University of Hong Kong, Hong Kong SAR, China.
Hao
H
Tang
Li-Guo
LG
Zhu
Liang
L
Zhao
Xuejin
X
Zhang
Jie
J
Shan
Shuit-Tong
ST
Lee
D003460:Crystallization / Q000379:methods*; D004553:Electric Conductivity; D004579:Electron Transport; D008027:Light; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D008968:Molecular Conformation; D010316:Particle Size; D012825:Silicon / Q000737:chemistry*; D020349:Surface Plasmon Resonance; D013499:Surface Properties
D046911:Macromolecular Substances; D012825:Silicon