Journal of the Korean Physical Society

pISSN 0374-4884 eISSN 1976-8524
Qrcode

Article

J. Korean Phy. Soc. 2009; 55(6): 2491-2495

Published online December 15, 2009     https://doi.org/10.3938/jkps.55.2491

Copyright © The Korean Physical Society.

Size Dependence of the Transport Properties of Silicon Nanostructures

S. J. Lee

Abstract

Silicon devices involving various p-type silicon nanostructures witha fixed length 20 $mu$m and thickness 40 nm, but with varying widthin the range from $sim$ 100 nm to 20 $mu$m, were prepared by usingthe top-down method in order to systematically study the widthdependence of their intrinsic transport property. Based on theI$_d$-V$_g$ characteristic measurements, the hole mobility($mu$$_h$) and concentration (n$_h$) were extracted for allnanostructures. For structures of large widths (w $>$ 1.0 $mu$m,nanoribbon-type), n$_h$ decreases from 5.5 to 2.4 $ imes$ 10$^{17}$cm$^{-3}$ while $mu$$_h$ increases from 160 to 380cm$^2$V$^{-1}$s$^{-1}$ as the width narrows down from 20 to 1.0$mu$m. Interestingly, however, n$_h$ and $mu$$_h$ are found to becorrelated such that their product remains nearly constant for thiswidth region, the origin of which is unclear. For structures ofsmall widths (w $leq$ 500 nm, nanowire-type), n$_h$ remains more orless constant at about 2.4 $ imes$ 10$^{17}$ cm$^{-3}$ while$mu$$_h$ decreases steadily from 340 to 240 cm$^2$V$^{-1}$s$^{-1}$as the width narrows down from 500 to 96 nm. This behavior ofmobility degradation with width narrowing in the nanowire region islikely to originate from the enhanced surface scattering effect, buta detailed microscopic theory should be developed to explain thiseffect quantitatively.

Keywords: Low-dimensional transport, Semiconductor, Nanowire