Study of trap states in zinc oxide (ZnO) thin films for electronic applications

The electrical properties of ZnO thin films grown by pulsed laser deposition were studied. Field-effect devices with a mobility reaching 1 cm2/V s show non-linearities both in the current–voltage and in the transfer characteristics which are explained as due to the presence of trap states. These traps cause a reversible threshold voltage shift as revealed by low-frequency capacitance–voltage measurements in metal insulator semiconductor (MIS) capacitors. Thermal detrapping experiments in heterojunctions confirm the presence of a trap state located at 0.32 eV

Provenance-enhanced Root Cause Analysis for Jupyter Notebooks

With Jupyter notebooks becoming more commonly used within scientific research, more Jupyter notebook-based use cases have evolved to be distributed. This trend makes it more challenging to analyze anomalies and debug notebooks. Provenance data is an ideal option that can create more context around anomalies and make it easier to find the root cause of the anomaly. However, provenance rarely gets investigated in the context of distributed Jupyter notebooks. In this paper, we propose a framework that integrates two data types, provenance and detected performance anomalies based on performance data. We use the combined information to visually show the enduser the provenance at the time of the anomaly and the root cause of the anomaly. We build and evaluate the framework with a notebook extended with anomaly-generating functions. The generated anomalies were automatically detected, and the combined information of provenance and anomaly creates a valuable subset of the provenance data around the time an anomaly occurred. Our experiments create a clear and confined context for the anomaly and enable the framework to find the root cause of performance anomalies in Jupyter notebooks.</p

Effect of Intra-molecular Disorder and Inter-molecular Electronic Interactions on the Electronic Structure of Poly-p-Phenylene Vinylene (PPV)

We investigate the role of intra-molecular conformational disorder and inter-molecular electronic interactions on the electronic structure of disorder clusters of poly-p-phenylene vinylene (PPV) oligomers. Classical molecular dynamics is used to determine probable molecular geometries, and first-principle density functional theory (DFT) calculations are used to determine electronic structure. Intra-molecular and inter-molecular effects are disentangled by contrasting results for densely packed oligomer clusters with those for ensembles of isolated oligomers with the same intra-molecular geometries. We find that electron trap states are induced primarily by intra-molecular configuration disorder, while the hole trap states are generated primarily from inter-molecular electronic interactions.Comment: 4 pages, 4 figures. Compile with pdflate

Electrical instabilities in organic semiconductors caused by trapped supercooled water

It is reported that the electrical instability known as bias stress is caused by the presence of trapped water in the organic layer. Experimental evidence as provided by the observation of an anomaly occurring systematically at around 200 K. This anomaly is observed in a variety of materials, independent of the deposition techniques and remarkably coincides with a known phase transition of supercooled water. Confined water does not crystallize at 273 K but forms a metastable liquid. This metastable water behaves electrically as a charge trap, which causes the instability. Below 200 K the water finally solidifies and the electrical traps disappear. (c) 2006 American Institute of Physics

Nanocomposite field effect transistors based on zinc oxide/polymer blends

The authors have examined the field effect behavior of nanocomposite field effect transistors containing ZnO (zinc oxide) tetrapods or nanocrystals dispersed in a polymer matrix of poly[2-methoxy,5-(2-ethylhexyloxy)-1,4- phenylenevinylene] (MEH-PPV). The electrical characteristics of ZnO tetrapods/MEH-PPV composite devices exhibit an increase in hole mobility up to three orders of magnitude higher than the polymer MEH-PPV device. © 2007 American Institute of Physics.published_or_final_versio

Effect of air distribution and spray liquid distribution of a cross-flow fan orchard sprayer on spray deposition in fruit trees

In a 4-year ongoing research programme in the Netherlands, we focus to maximise spray deposition in pome fruit trees and minimise spray deposition underneath the trees on the ground and minimise spray drift. For a cross-flow fan orchard sprayer we therefore measured spray deposition in the tree as an effect of different air settings and nozzle types. Nozzle types chosen were the Albuz ATR lilac (as a reference) and the Albuz TVI8001, both sprayed at 7 bar spray pressure. The orchard sprayer was a Munckhof cross-flow fan sprayer with a 2.75 m high cross-flow construction on top of the axial fan, equipped with 8 nozzles on both sides. At a forward speed of 6.5 km/h the spray volume was 200 L/ha and 290 L/ha, for respectively the Albuz lilac and Albuz TVI8001 nozzles. Air settings were: High air setting - 540 rpm PTO; and Low air setting - 540 rpm, 400 rpm, and 300 rpm PTO. Liquid distributions were measured with an AAMS-Salvarani Vertical patternator with discs, and air distribution was measured with a self-constructed measuring device equipped with ultrasonic anemometers and a handheld vane-anemometer. Liquid distribution in the apple trees (cv. Elstar) was measured in the full leaf growing stage (following ISO 22522). First results show a good correlation between air distribution and liquid distribution. Vertical liquid distribution measured on the liquid measuring device correlates also very good with the liquid distribution at different heights in the tree. However, air distribution and especially air speed of the orchard sprayer showed that decreasing air assistance increased the spray deposition in the fruit trees. Showing that air assistance is an important parameter to be taken up in the advice to fruit growers.In a 4-year ongoing research programme in the Netherlands, we focus to maximise spray deposition in pome fruit trees and minimise spray deposition underneath the trees on the ground and minimise spray drift. For a cross-flow fan orchard sprayer we therefore measured spray deposition in the tree as an effect of different air settings and nozzle types. Nozzle types chosen were the Albuz ATR lilac (as a reference) and the Albuz TVI8001, both sprayed at 7 bar spray pressure. The orchard sprayer was a Munckhof cross-flow fan sprayer with a 2.75 m high cross-flow construction on top of the axial fan, equipped with 8 nozzles on both sides. At a forward speed of 6.5 km/h the spray volume was 200 L/ha and 290 L/ha, for respectively the Albuz lilac and Albuz TVI8001 nozzles. Air settings were: High air setting - 540 rpm PTO; and Low air setting - 540 rpm, 400 rpm, and 300 rpm PTO. Liquid distributions were measured with an AAMS-Salvarani Vertical patternator with discs, and air distribution was measured with a self-constructed measuring device equipped with ultrasonic anemometers and a handheld vane-anemometer. Liquid distribution in the apple trees (cv. Elstar) was measured in the full leaf growing stage (following ISO 22522). First results show a good correlation between air distribution and liquid distribution. Vertical liquid distribution measured on the liquid measuring device correlates also very good with the liquid distribution at different heights in the tree. However, air distribution and especially air speed of the orchard sprayer showed that decreasing air assistance increased the spray deposition in the fruit trees. Showing that air assistance is an important parameter to be taken up in the advice to fruit growers

Minority-carrier effects in poly-phenylenevinylene as studied by electrical characterization

Electrical measurements have been performed on poly[2-methoxy, 5 ethyl (2' hexyloxy) paraphenylenevinylene] in a pn junction with silicon. These included current-voltage measurements, capacitance-voltage measurements, capacitance-transient spectroscopy, and admittance spectroscopy. The measurements show evidence for large minority-carrier injection into the polymer possibly enabled by interface states for which evidence is also found. The shallow acceptor level depth (0.12 eV) and four deep trap level activation energies (0.30 and 1.0 eV majority-carrier type; 0.48 and 1.3 eV minority-carrier type) are found. Another trap that is visible at room temperature has point-defect nature. (C) 2001 American Institute of Physics

Effect van spoorbreedte en balansverbetering op de drift

Een alternatief waarmee een behoorlijke driftreductie bereikt zou kunnen worden is de verbetering van de balans van spuitmachines door spoorbreedte vergroting van 1,50 naar 2,25 m, zeker in combinatie met rijpaden. Balansverbetering gecombineerd met driftarme doppen en een verlaging van de spuitboom van 50 naar 40 cm zou extra driftreductie kunnen geven. In een veldonderzoek werden de effecten van een grotere spoorbreedte, en daarmee een balansverbetering, op de drift gekwantificeerd. Daarnaast werd tijdens de bespuitingen de actuele spuitboomhoogte gemeten

Silicon vacancy containing two hydrogen atoms studied with electron paramagnetic resonance and infrared absorption spectroscopy, Phys

Float-zone and Czochralski-grown silicon crystals have been implanted with protons or deuterons. Electronparamagnetic-resonance measurements performed during illumination with light at 1064 nm reveal a signal, labeled DK5, in addition to the well-known signal from VO*-the excited spin-triplet state of the oxygenvacancy defect. The DK5 signal originates from a spin-triplet state of a vacancy-type defect with monoclinic-I ͑near-orthorhombic-I͒ symmetry. In contrast to the VO* signal, DK5 has about the same intensity in the spectra recorded on oxygen-lean and oxygen-rich samples, which indicates that the DK5 defect is not oxygen related. However, the close resemblance between the D tensors of DK5 and VO* strongly suggests that the electron-spin distributions are similar in the two defects. Moreover, anisotropic hyperfine splittings from two proton spins are partially resolved in the DK5 signal. The signal is assigned to VH 2 * , the excited spin-triplet state of the silicon vacancy containing two hydrogen atoms, which is the simplest defect consistent with the observed properties. The isochronal annealing behavior of DK5 coincides with that of two infrared-absorption lines at 2063 and 2077 cm Ϫ1 , which, like DK5, are observable only during illumination. These lines are assigned to Si-H stretch modes of VH 2 *