Optimization of Transistor Characteristics and Charge Transport in Solution Processed ZnO Thin Films Grown from Zinc Neodecanoate

Abstract Solution processing of metal oxide-based semiconductors is an attractive route for low-cost fabrication of thin films devices. ZnO thin films were synthesized from one-step spin coating-pyrolysis technique using zinc neodecanoate precursor. X-ray diffraction (XRD), UV–visible optical transmission spectrometry and photoluminescence spectroscopy suggested conversion to polycrystalline ZnO phase for decomposition temperatures higher than 400 °C. A 15 % precursor concentration was found to produce optimal TFT performance on annealing at 500 °C, due to generation of sufficient charge percolation pathways. The device performance was found to improve upon increasing the annealing temperature and the optimal saturation mobility of 0.1 cm2 V−1 s−1 with ION/IOFF ratio ~ 107 was achieved at 700 °C annealing temperature. The analysis of experimental results based on theoretical models to understand charge transport envisaged that the grain boundary depletion region is major source of deep level traps and their effective removal at increased annealing temperature leads to evolution of transistor performance. Graphic Abstract Single-step spin coating-pyrolysis synthesis of ZnO thin films from non-aqueous precursor zinc neodecanoate has been investigated for transistor applications. </jats:sec

Exchange bias in laterally oxidized Au/Co/Au nanopillars

Au/Co/Au nanopillars fabricated by colloidal lithography of continuous trilayers exhibit and enhanced coercive field and the appearance of an exchange bias field with respect to the continuous layers. This is attributed to the lateral oxidation of the Co interlayer that appears upon disc fabrication. The dependence of the exchange bias field on the Co nanodots size and on the oxidation degree is analyzed and its microscopic origin clarified by means of Monte Carlo simulations based on a model of a cylindrical dot with lateral core/shell structure.Comment: 8 pages, 4 figures. Published in Appl. Phys. Let

Coupling of individual quantum emitters to channel plasmons.

Efficient light-matter interaction lies at the heart of many emerging technologies that seek on-chip integration of solid-state photonic systems. Plasmonic waveguides, which guide the radiation in the form of strongly confined surface plasmon-polariton modes, represent a promising solution to manipulate single photons in coplanar architectures with unprecedented small footprints. Here we demonstrate coupling of the emission from a single quantum emitter to the channel plasmon polaritons supported by a V-groove plasmonic waveguide. Extensive theoretical simulations enable us to determine the position and orientation of the quantum emitter for optimum coupling. Concomitantly with these predictions, we demonstrate experimentally that 42% of a single nitrogen-vacancy centre emission efficiently couples into the supported modes of the V-groove. This work paves the way towards practical realization of efficient and long distance transfer of energy for integrated solid-state quantum systems.E.B.-U., R.M., M.G. and R.Q. acknowledge the European Community’s Seventh Framework Programme (grant ERC- Plasmolight; no. 259196) and Fundació privada CELLEX. E.B.-U. acknowledges support of the FPI fellowship from the Spanish MICINN. R.M. acknowledges support of Marie Curie and NEST fellowships. C.G.-B. and F.J.G.-V. acknowledge the European Research Council (ERC-2011-AdG, Proposal No. 290981). C.G.-B., E.M., and F.J.G.-V. acknowledge the Spanish MINECO (Contract No. MAT2011-28581-C02-01). C.G.-B. acknowledges support of the FPU fellowship from the Spanish MECD. I.P.R., T.H. and S.I.B. acknowledge financial support for this work from the Danish Council for Independent Research (the FTP project ANAP, Contract No. 09-072949) and from the European Research Council, Grant No. 341054 (PLAQNAP). Y.A. acknowledges the support of RYC-2011-08471 fellowship from MICINN. We thank Luis Martin-Moreno and Cesar E. García for fruitful discussions, Jana M. Say and Louise J. Brown for providing the ND solution, and Ioannis Tsioutsios for support with the AFM manipulation technique.This is the final published version. It first appeared at http://www.nature.com/ncomms/2015/150807/ncomms8883/full/ncomms8883.html

Optimization of Transistor Characteristics and Charge Transport in Solution Processed ZnO Thin Films Grown from Zinc Neodecanoate

Abstract: Solution processing of metal oxide-based semiconductors is an attractive route for low-cost fabrication of thin films devices. ZnO thin films were synthesized from one-step spin coating-pyrolysis technique using zinc neodecanoate precursor. X-ray diffraction (XRD), UV–visible optical transmission spectrometry and photoluminescence spectroscopy suggested conversion to polycrystalline ZnO phase for decomposition temperatures higher than 400 °C. A 15 % precursor concentration was found to produce optimal TFT performance on annealing at 500 °C, due to generation of sufficient charge percolation pathways. The device performance was found to improve upon increasing the annealing temperature and the optimal saturation mobility of 0.1 cm2 V−1 s−1 with ION/IOFF ratio ~ 107 was achieved at 700 °C annealing temperature. The analysis of experimental results based on theoretical models to understand charge transport envisaged that the grain boundary depletion region is major source of deep level traps and their effective removal at increased annealing temperature leads to evolution of transistor performance. Graphic Abstract: Single-step spin coating-pyrolysis synthesis of ZnO thin films from non-aqueous precursor zinc neodecanoate has been investigated for transistor applications.[Figure not available: see fulltext.

Spectral tunability of a plasmonic antenna with a dielectric nanocrystal.

We show that the positioning of a nanometer length scale dielectric object, such as a diamond nanocrystal, in the vicinity of a gold bowtie nanoantenna can be used to tune the plasmonic mode spectrum on the order of a linewidth. We further show that the intrinsic luminescence of gold enhanced in the presence of nanometer-scale roughness couples efficiently to the plasmon mode and carries the same polarization anisotropy. Our findings have direct implications for cavity quantum electrodynamics related applications of hybrid antenna-emitter complexes

Plasmonic Sensing Characteristics o f Single Nanometric Holes

The optical response of isolated holes in 20 nm thin gold is probed as a function of alkanethiol CH3(CH2)(x)SH (x is an element of 1-15) and protein adsorption using dark-field spectroscopy. We establish that the plasmon excitations of single and short-range ordered 60 nm holes exhibit similar E-field decay lengths delta approximate to 10-20 nm and that a single hole can be used to resolve the successive adsorption of a protein (biotin-BSA) and its interaction partner (neutravidin). The data confirm the localized character of the hole plasmon and demonstrate that its applicability for bio/chemosensing is similar to that of particle plasmons

Solution-Processed High-Performance ZnO Nano-FETs Fabricated with Direct-Write Electron-Beam-Lithography-Based Top-Down Route

Zinc oxide (ZnO) has been extensively investigated for use in large-area electronics; in particular, the solution-processing routes have shown increasing promise towards low-cost fabrication. However, top-down fabrication approaches with nanoscale resolution, towards aggressively scaled device platforms, are still underexplored. This study reports a novel approach of direct-write electron-beam lithography (DW-EBL) of solution precursors as negative tone resists, followed by optimal precursor processing to fabricate micron/nano-field-effect transistors (FETs). It is demonstrated that the mobility and current density of ZnO FETs can be increased by two orders of magnitude as the precursor pattern width is decreased from 50 µm to 100 nm. These nano-FET devices exhibit field-effect mobility exceeding ≈30 cm2 V−1 s−1 and on-state current densities reaching 10 A m−1, the highest reported so far for direct-write precursor-patterned nanoscale ZnO FETs. Using atomic force microscopy and parametric modeling, the origin of such device performance improvement is investigated. The findings emphasize the influence of pre-decomposition nanoscale precursor patterning on the grain morphology evolution in ZnO and, consequently, open up large-scale integration, and miniaturization opportunities for solution-processed, high-performance nanoscale oxide FETs