26 research outputs found
Influence of hydrogen and hydrogen/methane plasmas on AlN thin films
No full textPolycrystalline aluminum nitride (AlN) thin films are exposed to hydrogen and hydrogen/methane plasmas at different conditions. The latter plays an indispensable role in the subsequent deposition of nanocrystalline diamond thin films on AlN. The changes of AlN properties are investigated by means of Fourier transform infrared (FTIR) and Raman spectroscopies as well as atomic force microscopy. The E1(TO) and E22 phonon mode frequencies blue-shift after the exposure to plasmas. The damping constant of E1(TO) phonon, calculated from FTIR transmission spectra using the factorized model of a damped oscillator, and the width of E22 peak in Raman spectra decrease with increasing substrate temperature till the decomposition of AlN thin film becomes notable. It is proven that these changes are driven by the plasmas as annealing in vacuum does not induce them.Research Foundation Flanders (FWO) (G.0568.10N) and the EU FP7 through Marie Curie ITN “MATCON” (PITN-GA-2009-238201)
Enhanced performance of polymer: fullerene bulk heterojunction solar cells upon graphene addition
No full textGraphene has potential for applications in solar cells. We show that the short circuit current density of P3HT (Poly(3-hexylthiophene-2,5-diyl):PCBM((6,6)-Phenyl C61 butyric acid methyl ester) solar cells is enhanced by 10% upon the addition of graphene, with a 15% increase in the photon to electric conversion efficiency. We discuss the performance enhancement by studying the crystallization of P3HT, as well as the electrical transport properties. We show that graphene improves the balance between electron and hole mobilities with respect to a standard P3HT:PCBM solar cell. (C) 2014 AIP Publishing LLC
Dexter
No full textThe colour slides have been scanned with a HP ScanJet 5590 scanner; 24-bit true colour, 600 dpi, saved in JPEG-format. Downscaling was done with Adobe Photoshop.Photo 1: Original scanned document size: (w)85.37 x (h)56.44 cm. Final web-ready size: (w)7.62 x(h)5.04 cm, 46.22 kb, 150 ppi. Estimated download time: 17 sec. @ 28.8 kbps.COUNTRY OF ORIGIN: Breed of miniature Irish cattle reported in 1776, only called Dexters as of early 1800's (Ireland).SIZE: Dwarf/miniature.COLOUR: Black, red and dun.PURPOSE: Dual purpose.ADDITIONAL INFORMATION: Small docile dual purpose, used for beef, dairy, vegetation management and [email protected]
Thick homoepitaxial (110)-oriented phosphorus-doped n-type diamond
No full textAbstract: The fabrication of n-type diamond is essential for the realization of electronic components for extreme environments. We report on the growth of a 66 mu m thick homoepitaxial phosphorus-doped diamond on a (110)-oriented diamond substrate, grown at a very high deposition rate of 33 mu m h(-1). A pristine diamond lattice is observed by high resolution transmission electron microscopy, which indicates the growth of high quality diamond. About 2.9 x 10(16) cm(-3) phosphorus atoms are electrically active as substitutional donors, which is 60% of all incorporated dopant atoms. These results indicate that P-doped (110)-oriented diamond films deposited at high growth rates are promising candidates for future use in high-power electronic applications. Published by AIP Publishing
The Combined Effect of Practical Operating Conditions and Materials Choice on the Performance of Induction Machines
No full textIn this paper, the effect of practical operating conditions on induction motors and their performance is addressed. Mainly the effect of voltage unbalance on the efficiency will be investigated. The performance of an electromagnetic actuator depends on design or technological choices and on the volume and characteristics of the materials that are used. Therefore, this paper focuses on the influence of these design aspects on the performance of induction motors which are supplied by unbalanced voltage. Experiments reveal that differences in material choice in induction motors, e.g. Al vs. Cu rotor technology, result in interesting differences in behaviour in the presence of voltage unbalance. These results are thoroughly discussed and explained in the paper
Nanodiamond seeding on plasma-treated tantalum thin films and the role of surface contamination
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