Here, we demonstrate that quasi self-standing Au nanorod arrays prepared with plasma polymerisation deposited SiO2 dielectric spacers support surface enhanced fluorescence (SEF) while maintaining high signal reproducibility. We show that it is possible to find a balance between enhanced radiative and non-radiative decay rates at which the fluorescent intensity is maximized. The SEF signal optimised with a 30 nm spacer layer thickness showed a 3.5-fold enhancement with a signal variance of <15% thereby keeping the integrity of the nanorod array. We also demonstrate the decreased importance of obtaining resonance conditions when localized surface plasmon resonance is positioned within the spectral region of Au interband transitions. Procedures for further increasing the SEF enhancement factor are also discussed.
In addition to titanium grade 5, both cobalt chromium and stainless steel 316 were investigated. In this study HA coatings were deposited using both the CoBlast and plasma sprayed techniques, and the resultant HA coating and substrate properties were evaluated and compared. The CoBlast deposited HA coatings were found to present similar surface morphologies, interfacial properties and composition irrespective of the substrate alloy type. Coating thickness however displayed some variation with the substrate alloy, ranging from 2.0 to 3.0 μm.This perhaps is associated with the electro-negativity of the metal alloys. The APS treated samples exhibited evidence of both coating, and significantly, substrate phase alterations for two metal alloys; titanium grade 5 and cobalt chrome. Conversely, the CoBlast processed samples exhibited no phase changes to the substrates after depositions. The APS alterations were attributed to the brief, but high intensity temperatures experienced during processing.
This paper compares the properties of hydroxyapatite (HA) coatings, obtained using two different deposition technologies on Ti-6Al-4V substrates. The deposition techniques evaluated were: atmospheric plasma spray (APS, thermal treatment) and a novel micro-blasting technique known as CoBlast (non-thermal treatment). The HA coatings were examined with respect to their morphology, crystallinity and adhesion, while the phase concentration of the metallic substrates were also analysed. In vitro cell proliferation and cell morphology studies using MG-63 osteoblastic cells were carried out on the HA coated substrates obtained using the two deposition techniques, with untreated titanium grade 5 (Ti-6Al-4V) substrates utilised as a control. XRD analysis of the CoBlast deposited HA coatings demonstrated that it was comprised of the same crystalline HA as the precursor powder. For the APS HA coatings however, additional calcium phosphate phases were observed, and these were attributed to phase changes caused by the high plasma deposition temperatures. The APS treated samples also exhibited evidence of substrate modification, with substrate conversion to a β-rich surface at the HA/substrate interface was observed in the XRD analysis. CoBlast HA coatings, with an average thickness of approx. 2.5 µm, were found to have higher tensile adhesion values (33.6 and 35.7MPa), when compared with the 5 MPa obtained for the approx. 26.9 µm thick APS coatings using a modified tensile adhesion test. This lower adhesion tensile value is most likely due to the increased residual stress generated in the HA coating during thermal plasma processing. The cell response studies on the four surfaces tested indicate that the HA surfaces exhibited higher levels of cell proliferation than the untreated titanium after 5 days, with the CoBlast surfaces displaying statically significant increases in cell proliferation.3
With increasing miniaturization in microelectronics, one of the challenges to maintaining device performance is the management of excess heat. The room-temperature thermoelectric efficiencies of bismuth telluride (BiTe) compounds are the highest reported for any material. Therefore, BiTe nanowires are interesting as building blocks of thermoelectric circuits that can be used for heat management. Further improvements in nanoscale thermoelectrics may lead to new applications such as nanoscale room temperature coolers and generators, and uncooled bolometers. The exploitation of the thermoelectric properties of devices based on nanowires of thermoelectric materials requires good electrical contacts between the nanowires and metal electrodes and this is the subject of the present report.We present a study of the contact resistance and methods for controlling its value in individual bismuth telluride nanowires. The wires are fabricated by employing a two step method. First, dense arrays of 200-nm bismuth telluride nanowires are prepared by a nonlithographic fabrication technique consisting of the pressure injection of an alumina template with molten bismuth telluride. In the second step, individual nanowires are removed from the template by etching the alumina. The two step method has the advantage that, as we will show, some of the nanowires' properties can be characterized by performing measurements on the arrays. In our investigations, we employed a simple device consisting of attaching a bismuth telluride nanowire to two gold planar electrodes. We find that the contact resistance has the potential of being non-ohmic and therefore lead to non-equilibrium Section I. IntroductionThe material science of bismuth telluride nanowires has advanced to the point that many methods for preparing and characterizing individual BiTe nanowires are available. There have been several previous reports of discrete bismuth telluride nanowire fabrication by laser ablation.' There have also been reports of the synthesis of individual bismuth telluride nanowires by cyclic electrodeposition/stripping coupled with electrochemical step edge decoration.2 In these methods the wire diameter is determined by processing variables. A simpler approach to defining the wire diameter is to separate the steps of nanowire synthesis and isolation. Uniform diameter nanowires can be grown in arrays employing the template strategy where materials consisting of arrays of channels of the chosen diameter, such as porous anodic alumina, are impregnated with a solid solution of the chosen composition. One method of filling the channels is electrodeposition into porous anodic alumina templates.3-7 The thermoelectric properties of the nanowires can be measured employing microfabricated devices. One method employs two adjacent silicon nitride membranes, each suspended in vacuum and away from the substrate by long beams and therefore isolated thermally. The silicon nitride membranes serve as substrates for serpentine Pt lines that can be used as electrical resistanc...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.