Browsing by Author "Wang, Shiu-Yu"

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Effects of low-temperature Si buffer thickness and SiGe oxidation on sensitivity of Si1-xGex nanowire
(2015-06-01)
Lai, Yi-Lung
;
Chang, Tai-Yuan
;
Chang, Kow-Ming
;
Chen, Chu-Feng
;
Lai, Chiung-Hui
Si1-xGex nanowire biosensors are attractive for their high sensitivity due to the large surface-to-volume ratio, high carrier mobility, and silicon compatibility. In this work, we study the effect of the thickness of the low-temperature Si (LT-Si) buffer layer on an insulator on the sensitivity of oxidized Si1-xGex nanowire samples with different Ge contents by increasing the Si buffer thickness from 20 to 60 nm. 3-Aminopropyltrimethoxy-silane (APTMS) was used as a biochemical reagent. It was demonstrated that, with the proper Ge content and LT-Si buffer thickness, the sensitivity of the Si1-xGex nanowire is high and it can be further improved by Si1-xGex oxidation. This can be attributed to the reduction of the diameter to the nanometer order, which gives rise to an increased surface-to-volume ratio and further enhances the sensitivity of the biosensor. (C) 2015 The Japan Society of Applied Physics
Influence of Surface State on Biochemical Sensing Using SiGe Nanowire
(2015-06-01)
Lai, Chiung-Hui
;
Chang, Kow-Ming
;
Chen, Yi-Ming
;
Chen, Chu-Feng
;
Kuo, Po-Shen
Nanowires are extensively used to fabricate highly sensitive electrical sensors for detection of biological and chemical species. The hole mobility can be promoted by the increasing Ge fraction in SiGe, achieved by the oxidation-induced Ge condensation. However, oxidation increases the number of surface states, which brings the nonnegligible contribution in mobility degradation. In this work, 3-aminopropyltrimethoxysilane (APTMS) was used as a biochemical reagent to modify the surface of SiGe nanowires, then bonding to bio-linker, bis (3-sulfo-N-hydroxysuccinimide ester) sodium salt (BS3). Various methods have been proposed for increasing sensitivity of boron-doped SiGe nanowires, such as capping layer, surface treatment, and annealing temperature.