Browsing by Subject "Gold coatings"

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    Comparative study of thin film n-i-p a-Si: H solar cells to investigate the effect of absorber layer thickness on the plasmonic enhancement using gold nanoparticles
    (Elsevier Ltd, 2015) Islam, K.; Chowdhury F.I.; Okyay, Ali Kemal; Nayfeh, A.
    In this paper, the effect of gold nanoparticles on n-i-p a-Si:H solar cells with different intrinsic layer (i-layer) thicknesses has been studied. 100nm and 500nm i-layer based n-i-p a-Si:H solar cells were fabricated and colloidal gold (Au) nanoparticles dispersed in water-based solution were spin-coated on the top surface of the solar cells. The Au nanoparticles are of spherical shape and have 100nm diameter. Electrical and quantum efficiency measurements were carried out and the results show an increase in short-circuit current density (Jsc), efficiency and external quantum efficiency (EQE) with the incorporation of the nanoparticles on both cells. Jsc increases from 5.91mA/cm2 to 6.5mA/cm2 (~10% relative increase) and efficiency increases from 3.38% to 3.97% (~17.5% relative increase) for the 100nm i-layer solar cell after plasmonic enhancement whereas Jsc increases from 9.34mA/cm2 to 10.1mA/cm2 (~7.5% relative increase) and efficiency increases from 4.27% to 4.99% (~16.9% relative increase) for the 500nm i-layer cell. The results show that plasmonic enhancement is more effective in 100nm than 500nm i-layer thickness for a-Si:H solar cells. Moreover, the results are discussed in terms of light absorption and electron hole pair generation. © 2015 Elsevier Ltd.
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    Wafer bonded capacitive micromachined underwater transducers
    (IEEE, 2009-09) Olcum, Selim; Oǧuz, Kaan; Şenlik, Muhammed N.; Yamaner F. Y.; Bozkurt, A.; Atalar, Abdullah; Köymen, Hayrettin
    In this work we have designed, fabricated and tested CMUTs as underwater transducers. Single CMUT membranes with three different radii and 380 microns of thickness are fabricated for the demonstration of an underwater CMUT element. The active area of the transducer is fabricated on top of a 3″ silicon wafer. The silicon wafer is bonded to a gold electrode coated glass substrate wafer 10 cm in diameter. Thermally grown silicon oxide layer is used as the insulation layer between membrane and substrate electrodes. Electrical contacts and insulation are made by epoxy layers. Single CMUT elements are tested in air and in water. Approximately 40% bandwidth is achieved around 25 KHz with a single underwater CMUT cell. Radiated pressure field due to second harmonic generation when the CMUTs are driven with high sinusoidal voltages is measured. ©2009 IEEE.