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Abstract
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Here, Zinc Oxide nanowires are synthesized using thermal chemical vapor deposition of a Zn
granulate source and used to enhance a significant Si-solar cell efficiency with simple and low cost
method. The nanowires are grown in variousO2 flow rates. Those affect the shape, yield, structure and
the quality of ZnO nanowires according to scanning electron microscopy and x-ray diffraction
analyses. This delineates that the ZnO nanostructure is dependent on the synthesis conditions. The
photoluminescence spectroscopy of ZnO indicates optical emission at the Ultra-Violet and blue–
green regions whose intensity varies as a function of diameter ofZnO nano-wires. The optical property
of ZnO layer is measured byUV–visible and diffuse reflection spectroscopy that demonstrate high
absorbance at 280–550 nm. Furthermore, the photovoltaic characterization of ZnO nanowires is
investigated based on the drop casting on Si-solar cell. The ZnO nanowires with various diameters
demonstrate different effects on the efficiency of Si-solar cells.Wehave shown that the reduction of
the spectral reflectance and down-shifting process as well as the reduction of photon trapping are
essential parameters on the efficiency of Si-solar cells. However, the latter is dominated here. In fact,
the trapped photons during the electron–hole generation are dominant due to lessening the
absorption rate in ZnO nano-wires. The results indicate that the mean diameters reduction of ZnO
nanowires is also essential to improve the fill factor. The external and internal quantum efficiency
analyses attest the efficiency improvement over the blue region which is related to the key parameters
above.
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