Publications (3) View all
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Conference Proceeding: Characterization of dielectric materials using a high-resolution scanning Kelvin-microprobe
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ABSTRACT: The scanning Kelvin microprobe is a powerful technique to characterize subtle changes in surface microstructure and local chemical properties through the simultaneously imaging of the topography and potential distribution across a surface at the sub-micron level. The study of dielectric materials using the Kelvin method opens a new area of applications for a technique traditionally reserved specifically for metals and, more recently, for semiconductor materials. We present here the capabilities of this new instrument, the characterization of dielectric samples and the related challenges, as well as Finite Element Analysis models of this particular type of insulating surfaces.Electrical Insulation and Dielectric Phenomena, 2003. Annual Report. Conference on; 11/2003 -
Article: Surface immobilized biochemical macromolecules studied by scanning Kelvin microprobe.
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ABSTRACT: The measurement of work function is a particularly effective method for the characterization of surfaces because of the sensitivity of the parameter to interfacial structure, modification and overall chemistry. Accordingly, techniques for the analysis of work function offer a powerful tool for monitoring surface chemical changes, especially for situations involving the immobilization of new moieties at the interface. In the present paper, we describe the performance of a new, modified scanning Kelvin microprobe which is capable of the tandem measurement of contact potential and surface topography with resolutions of 1 mV and 10 nm, respectively. The lateral resolution is 1 micron. The instrument has been applied to the study of substrates modified by the attachment of biochemical macromolecules such as oligonucleotides and DNA. This preliminary work confirms the great potential of the technique in the study of biocompatibility, macromolecular structure and microarray devices.Faraday Discussions 02/2000; · 5.00 Impact Factor -
Article: Work-function measurement by high resolution scanning Kelvin nanoprobe.
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ABSTRACT: Nanoscience promises to transform today's world in the same way that integrated semiconductor devices transformed the world of electronics and computation. In the post-genomic era, the greatest challenge is to make connections between the structures and functions of biomolecules at the nanometre-scale level in order to underpin the understanding of larger scale systems in the fields of human biology and physiology. To achieve this, instruments with new capabilities need to be researched and developed, with particular emphasis on new levels of sensitivity, precision and resolution for biomolecular analysis. This paper describes an instrument able to analyse structures that range from tenths of a nanometre (proteins, DNA) to micron-scale structures (living cells), which can be investigated non-destructively in their normal state and subsequently in chemical- or biochemical-modified conditions. The high-resolution scanning Kelvin nanoprobe (SKN) measures the work-function changes at molecular level, instigated by local charge reconfiguration due to translational motion of mobile charges, dipolar relaxation of bound charges, interfacial polarization and structural and conformational modifications. In addition to detecting surface electrical properties, the instrument offers, in parallel, the surface topographic image, with nanometre resolution. The instrument can also be used to investigate subtle work function/topography variations which occur in, for example, corrosion, contamination, adsorption and desorption of molecules, crystallographic studies, mechanical stress studies, surface photovoltaic studies, material science, biocompatibility studies, microelectronic characterization in semiconductor technology, oxide and thin films, surface processing and treatments, surfaces and interfaces characterization. This paper presents the design and development of the instrument, the basic principles of the method and the challenges involved to achieve nanometric resolution and sub-millivolt sensitivity, for both the topographic imaging of surface micromorphology and surface potential and work-function determination.
