Browsing by Subject "Amorphous Si"

Filter results by typing the first few letters
Now showing 1 - 3 of 3
  • Thumbnail Image
    ItemOpen Access
    Effect of gold nanoparticles size on light scattering for thin film amorphous-silicon solar cells
    (Elsevier Ltd, 2014-05) Islam, K.; Alnuaimi, A.; Battal, E.; Okyay, Ali Kemal; Nayfeh, A.
    In this work, the effect of gold (Au) nanoparticles on the performance of a-Si:H solar cells is investigated experimentally. The solar cell stack is grown on a highly doped p-type Si wafer and consists of 20nm heavily doped p-type a-Si, 500nm undoped a-Si, 20nm heavily doped n-type a-Si and finally 80nm Indium Tin Oxide (ITO) on the top. Au nanoparticles of 10, 20, 50, 80, 100, 200 and 400nm are spin coated on top of the ITO before metallization. The plasmonic effect of the Au nanoparticles allows for additional scattering at the surface thus reducing the overall reflectivity. The larger the nanoparticle size the more scattering is obtained and the median reflectivity drops from about 23% to 18%. The results show an increase in the short-circuit current density (Jsc) and efficiency with increasing nanoparticle size. The Jsc increases from 9.34 to 10.1mA/cm2. In addition, the efficiency increases from 4.28% to 5.01%. © 2014 Elsevier Ltd.
  • Thumbnail Image
    ItemOpen Access
    Improved efficiency of thin film a-Si:H solar cells with Au nanoparticles
    (Institute of Electrical and Electronics Engineers Inc., 2013) Islam, K.; Alnuaimi, A.; Okyay, Ali Kemal; Nayfeh, A.
    In this work, the effect of Au nanoparticles on the performance of a-Si:H solar cells is investigated experimentally. Au nanoparticles of 10, 20, 50, 80, 100, 200 and 400 nm are spin coated on ITO before metallization. The results show an increase in the Jsc and efficiency with increasing nanoparticle size. The Jsc increases from 9.34 mA/cm2 to 10.1 mA/cm2. In addition, the efficiency increases from 4.28% to 5.01%. © 2013 IEEE.
  • Thumbnail Image
    ItemOpen Access
    Synthesis, characterization, and wear and friction properties of variably structured SiC/Si elements made from wood by molten Si impregnation
    (2012) Dhiman, R.; Rana, K.; Bengu, E.; Morgen P.
    We have synthesized pre-shaped SiC/Si ceramic material elements from charcoal (obtained from wood) by impregnation with molten silicon, which takes place in a two-stage process. In the first process, a porous structure of connected micro-crystals of β-SiC is formed, while, in the second process, molten Si totally or partly infiltrates the remaining open regions. This process forms a dense material with cubic (β-)SiC crystallites, of which the majority is imbedded in amorphous Si. The synthesis of preshaped "sprocket" elements demonstrates that desired shapes of such a dense SiC/Si composite ceramic material can be achieved, thus suggesting new industrial applications. The structure and composition of numerous as-synthesized samples were characterized in detail by using a wide range of techniques. Wear and friction properties were also investigated, with polished samples. The properties found for the present samples are very promising for abrasive applications and for new generation brake systems. © 2011 Elsevier Ltd.