Electrical transport in ion beam created InAs nanospikes

Ion beam irradiation has previously been demonstrated as a method for creating nanowire-like semiconductor nanostructures, but no previous studies have reported on the electrical properties of those structures. In this work we describe the creation and in situ transmission electron microscopy electrical characterization of nanoscale InAs spike structures on both InAs and InP substrates fabricated using a focused ion beam erosion method. Those InAs ‘nanospikes’ are found to possess internal structures with varying amounts of ion damaged and single crystalline material. Nanospike electrical behavior is analyzed with respect to model electronic structures and is similar to cases of barrier limited conduction in nanowires. The different electrical responses of each nanospike are found to be the result of variation in their structure, with the conductivity of InAs nanospikes formed on InAs substrates found to increase with the degree of nanospike core crystallinity. The conductivity of InAs nanospikes formed on InP substrates does not show a dependence on core crystallinity, and may be controlled by the other internal barriers to conduction inherent in that system.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98603/1/0957-4484_23_31_315301.pd

Modern microwave methods in solid state inorganic materials chemistry: from fundamentals to manufacturing

No abstract available

Reactive synthesis of Ti-Al intermetallics during microwave heating in an E-field maximum

The time-resolved X-ray diffraction synchrotron radiation technique was used in combination with E-field microwave heating to study in situ the kinetics of intermetallic phase formation in the Ti-Al system. The reaction of Ti with Al is triggered by the melting and spreading of Al onto the surface of Ti particles. The tetragonal TiAl 3 phase is the primary reaction product, formed by instantaneous nucleation at the interface between the unreacted Ti cores and the Al melt. The growth of TiAl 3 layers is diffusion-controlled. These preliminary results demonstrate that microwave heating can be used to rapidly synthesise intermetallic phases from high-purity elemental powders. © 2010 Elsevier B.V. All rights reserved.This work has been supported by the Swiss National Science Foundation (Grant 20PA21E-129193).Vaucher, S.; Stir, M.; Ishizaki, K.; Catalá Civera, JM.; Nicula, R. (2011). Reactive synthesis of Ti-Al intermetallics during microwave heating in an E-field maximum. Thermochimica Acta. 522(1):151-154. doi:10.1016/j.tca.2010.11.026S151154522

Millennials in the Workplace: A Communication Perspective on Millennials’ Organizational Relationships and Performance

Stereotypes about Millennials, born between 1979 and 1994, depict them as self-centered, unmotivated, disrespectful, and disloyal, contributing to widespread concern about how communication with Millennials will affect organizations and how they will develop relationships with other organizational members. We review these purported characteristics, as well as Millennials’ more positive qualities—they work well in teams, are motivated to have an impact on their organizations, favor open and frequent communication with their supervisors, and are at ease with communication technologies. We discuss Millennials’ communicated values and expectations and their potential effect on coworkers, as well as how workplace interaction may change Millennials

²¹Ne and ¹³¹Xe NMR study of electric field gradients and multinuclear NMR study of the composition of a ferroelectric liquid crystal

Abstract This study has two goals. First, the electric field gradient (EFG) present in the liquid-crystalline phases of ferroelectric FELIX-R&D is determined using NMR spectroscopy of noble gases ²¹Ne and ¹³¹Xe. The ²¹Ne and ¹³¹Xe NMR spectra were recorded over a temperature range, which covers all the mesophases of FELIX-R&D: nematic N*, smectic A, and smectic C*. The spin quantum number of both ²¹Ne and ¹³¹Xe is 3/2. Their electric quadrupole moment interacts with the EFG at the nuclear site, which in liquid-crystalline phases results in the NMR spectra of the triplet structure, instead of a singlet detectable in the isotropic phase. The total EFG experienced by the noble gas nuclei consists of two contributions; one arises from the quadrupole moments of the liquid crystal molecules (external contribution) and the other one from the deformation of the electron distribution of the atoms (deformational contribution). The total EFGs determined from the ¹³¹Xe and ²¹Ne quadrupole splittings are very similar in the nematic and smectic A phases but differ in the smectic C* phase, being about twice larger in the ²¹Ne case which stems from the larger deformation of the xenon electron cloud than that of neon. For the first time, EFG was determined also in the smectic C* phase applying noble gas NMR spectroscopy. Second, the structure of molecules which, as a mixture, compose the used ferroelectric liquid crystal, FELIX-R&D, is determined by applying a number of various NMR methods and sophisticated spectral analysis. In this part, NMR spectra were recorded from FELIX-R&D/CDCl3 solution. The NMR spectral analysis was divided into four subsystems with over 13 000 000 nonzero intensity transitions. It appeared that FELIX-R&D is composed of three phenyl pyrimidine derivatives and a chiral dopant with fluorine in the asymmetric carbon atom

Clathrate structure determination by combining crystal structure prediction with computational and experimental ¹²⁹Xe NMR spectroscopy

Abstract We present an approach for the structure determination of clathrates using NMR spectroscopy of enclathrated xenon to select froma set of predicted crystal structures. Crystal structure prediction methods have been used to generate an ensemble of putative structures of o- and m-fluorophenol, whose previously unknown clathrate structures have been studied by ¹²⁹Xe NMR spectroscopy. The high sensitivity of the ¹²⁹Xe chemical shift tensor to the chemical environment and shape of the crystalline cavity makes it ideal as a probe for porous materials. The experimental powder NMR spectra can be used to directly confirm or reject hypothetical crystal structures generated by computational prediction, whose chemical shift tensors have been simulated using density functional theory. For each fluorophenol isomer we find one predicted crystal structure whose measured and computed chemical shift tensors agree within experimental and computational error margins and these are thus proposed as the true fluorophenol xenon clathrate structures