Evidence of space charge regions within semiconductor nanowires from Kelvin probe force microscopy

Narvaez, A.C.; Chiaramonte, T.; Vicaro, Klaus Orian; Clerici, João Hermes; Cotta, M. A.

doi:10.1088/0957-4484/20/46/465705

Cited by 12 publications

(8 citation statements)

References 36 publications

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“…In the Amplitude Mode-Kelvin Probe Force Microscopy technique used here, we define the ‘zero’ SP value for the first point of the image; thus only variations of SP along the image can be compared quantitatively. Therefore, in order to compare SP values from different surfaces and thus exclude tip effects arising from metal coating wear [29] we have used the Si substrate as a common reference in the images; for that we have scanned edges of the cellulose film which show the Si substrate as well. We thus compare absolute SP* values from the different samples according to the following equation: SP* = SP(cellulose) – SP(Si).…”

Section: Methodsmentioning

confidence: 99%

Surface Physicochemical Properties at the Micro and Nano Length Scales: Role on Bacterial Adhesion and Xylella fastidiosa Biofilm Development

et al. 2013

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The phytopathogen Xylella fastidiosa grows as a biofilm causing vascular occlusion and consequently nutrient and water stress in different plant hosts by adhesion on xylem vessel surfaces composed of cellulose, hemicellulose, pectin and proteins. Understanding the factors which influence bacterial adhesion and biofilm development is a key issue in identifying mechanisms for preventing biofilm formation in infected plants. In this study, we show that X. fastidiosa biofilm development and architecture correlate well with physicochemical surface properties after interaction with the culture medium. Different biotic and abiotic substrates such as silicon (Si) and derivatized cellulose films were studied. Both biofilms and substrates were characterized at the micro- and nanoscale, which corresponds to the actual bacterial cell and membrane/ protein length scales, respectively. Our experimental results clearly indicate that the presence of surfaces with different chemical composition affect X. fastidiosa behavior from the point of view of gene expression and adhesion functionality. Bacterial adhesion is facilitated on more hydrophilic surfaces with higher surface potentials; XadA1 adhesin reveals different strengths of interaction on these surfaces. Nonetheless, despite different architectural biofilm geometries and rates of development, the colonization process occurs on all investigated surfaces. Our results univocally support the hypothesis that different adhesion mechanisms are active along the biofilm life cycle representing an adaptation mechanism for variations on the specific xylem vessel composition, which the bacterium encounters within the infected plant.

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Section: Methodsmentioning

confidence: 99%

Surface Physicochemical Properties at the Micro and Nano Length Scales: Role on Bacterial Adhesion and Xylella fastidiosa Biofilm Development

et al. 2013

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“…Photoluminescence (PL) studies were performed using micro-PL setup with 325 nm excitation. Topography and SP images were acquired simultaneously using an Agilent 5500 with a three-lock-in amplifier in the amplitude modulation KPFM. , For the measurements, V AC bias at frequencies in the range 10−15 kHz plus a DC bias, V DC , were applied between tip and sample. The detector signal amplitude at the V AC frequency should be proportional to ( V DC − Δϕ) V AC ∂ C /∂ z , where C and z are the capacitance and distance between tip and sample, respectively .…”

mentioning

confidence: 99%

Enhanced Surface Potential Variation on Nanoprotrusions of GaN Microbelt As a Probe for Humidity Sensing

et al. 2011

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Surface potential (SP) using Kelvin probe microscopy is employed, as a measure to sense humidity, exploiting localized nanoprotrusions of freestanding GaN microbelts. These belts with distinct nanofeatures are grown using chemical vapor deposition technique in the vapor−solid process. The variation of SP value is associated with the surface charge accumulation. Pronounced enhancement of the SP variation is found to arise from the localized inhomogeneity on the nanoprotrusions of microbelt. Role of oxygen-related native defect complexes is also discussed for the observed SP variation with humidity. Furthermore, the rough surface of belts favors a high level of defects on the surface and appears more sensitive to moisture level in atmosphere. Hence attention is essential for any sensing application of chemical species using GaN. A dissociative path way for the reaction mechanism of water molecules on GaN surfaces has been predicted.

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“…The reported MCD and LOD results are quite remarkable considering the simplicity of the InP nanowire device for biosensing tests, working with no field effect amplification and average nanowire diameters larger than surface depleted regions. 72 Moreover, despite the good receptor uniformity and capture binding performance exhibited by our functionalization protocol, no further receptor density optimization was performed prior to the biosensing tests. Table 1.…”

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confidence: 99%

InP Nanowire Biosensor with Tailored Biofunctionalization: Ultrasensitive and Highly Selective Disease Biomarker Detection

et al. 2017

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Electrically active field-effect transistors (FET) based biosensors are of paramount importance in life science applications, as they offer direct, fast, and highly sensitive label-free detection capabilities of several biomolecules of specific interest. In this work, we report a detailed investigation on surface functionalization and covalent immobilization of biomarkers using biocompatible ethanolamine and poly(ethylene glycol) derivate coatings, as compared to the conventional approaches using silica monoliths, in order to substantially increase both the sensitivity and molecular selectivity of nanowire-based FET biosensor platforms. Quantitative fluorescence, atomic and Kelvin probe force microscopy allowed detailed investigation of the homogeneity and density of immobilized biomarkers on different biofunctionalized surfaces. Significantly enhanced binding specificity, biomarker density, and target biomolecule capture efficiency were thus achieved for DNA as well as for proteins from pathogens. This optimized functionalization methodology was applied to InP nanowires that due to their low surface recombination rates were used as new active transducers for biosensors. The developed devices provide ultrahigh label-free detection sensitivities ∼1 fM for specific DNA sequences, measured via the net change in device electrical resistance. Similar levels of ultrasensitive detection of ∼6 fM were achieved for a Chagas Disease protein marker (IBMP8-1). The developed InP nanowire biosensor provides thus a qualified tool for detection of the chronic infection stage of this disease, leading to improved diagnosis and control of spread. These methodological developments are expected to substantially enhance the chemical robustness, diagnostic reliability, detection sensitivity, and biomarker selectivity for current and future biosensing devices.

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Evidence of space charge regions within semiconductor nanowires from Kelvin probe force microscopy

Cited by 12 publications

References 36 publications

Surface Physicochemical Properties at the Micro and Nano Length Scales: Role on Bacterial Adhesion and Xylella fastidiosa Biofilm Development

Surface Physicochemical Properties at the Micro and Nano Length Scales: Role on Bacterial Adhesion and Xylella fastidiosa Biofilm Development

Enhanced Surface Potential Variation on Nanoprotrusions of GaN Microbelt As a Probe for Humidity Sensing

InP Nanowire Biosensor with Tailored Biofunctionalization: Ultrasensitive and Highly Selective Disease Biomarker Detection

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