Abstract
A top-down nanofabrication approach is used to develop silicon nanowires from silicon-on-insulator (SOI) wafers and involves direct-write electron beam lithography (EBL), inductively coupled plasma-reactive ion etching (ICP-RIE) and a size reduction process. To achieve nanometer scale size, the crucial factors contributing to the EBL and size reduction processes are highlighted. The resulting silicon nanowires, which are 20 nm in width and 30 nm in height (with a triangular shape) and have a straight structure over the length of 400 μm, are fabricated precisely at the designed location on the device. The device is applied in biomolecule detection based on the changes in drain current (Ids), electrical resistance and conductance of the silicon nanowires upon hybridization to complementary target deoxyribonucleic acid (DNA). In this context, the scaled-down device exhibited superior performances in terms of good specificity and high sensitivity, with a limit of detection (LOD) of 10 fM, enables for efficient label-free, direct and higher-accuracy DNA molecules detection. Thus, this silicon nanowire can be used as an improved transducer and serves as novel biosensor for future biomedical diagnostic applications.
Highlights
Silicon nanowires with nanometer-scale widths and micrometer-scale lengths are receiving considerable attention for sensor applications, and many research groups have demonstrated these materials’ promising nanotechnology and exciting potential for use in the future “Biosensing” era [1,2,3,4,5,6,7]
The results show that dry etching process produced a silicon nanowire with more surface roughness and greater width, which is in agreement with the findings of Enami et al [37]
High-quality silicon nanowires with good performance as a biosensor were successfully fabricated via a top-down nanofabrication approach
Summary
Silicon nanowires with nanometer-scale widths and micrometer-scale lengths are receiving considerable attention for sensor applications, and many research groups have demonstrated these materials’ promising nanotechnology and exciting potential for use in the future “Biosensing” era [1,2,3,4,5,6,7]. The fabrication of silicon nanowires has been demonstrated by both bottom-up [3, 15, 24] and top-down [3, 8, 14, 22, 24,25,26] approaches. The bottom-up approach usually uses metal-catalytic growth [4, 27]. Difficulty in PLOS ONE | DOI:10.1371/journal.pone.0152318 March 29, 2016
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