Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/27473
Title: Use of surface modified porous silicon as a chemical or bio-chemical sensor
Authors: CHAMILA NISHANTHI LIYANAGE
Keywords: Porous silicon, surface modification, chemical sensor, surface tension,permitivity, impedance
Issue Date: 12-Jul-2010
Source: CHAMILA NISHANTHI LIYANAGE (2010-07-12). Use of surface modified porous silicon as a chemical or bio-chemical sensor. ScholarBank@NUS Repository.
Abstract: Electrochemically formed porous silicon sensors show a very high specific surface area ratio but poor chemical stability. This is overcome by surface modification, which also enhances the selectivity. In the present work an impedance based PSi sensor was fabricated and subjected to three different types of tests in which the sensor was exposed to either: static drop; flowing liquid; or saturated vapour. Sensors with different surface functional groups influence the extent of the interaction with target analytes, thereby providing a means of selectivity. Reasonable linear correlations existed between the changes in the impedance of sensors with chemically inert surfaces and both the surface tension and the dielectric properties of the target analytes, whereas sensors with surface functionalities of ?COOH and NH2 deviated from linearity due to H-bonding. A model based on treating PSi as a series of capacitive plates has been developed to help explain the mechanism behind sensing action.
URI: http://scholarbank.nus.edu.sg/handle/10635/27473
Appears in Collections:Ph.D Theses (Open)

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