Growth And Characterization Of Cdo Structures For Solar Cell Application
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Date
2015-01
Authors
MOHAMMED, MUSTAFA ZAIEN
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Abstract
Different structures of cadmium oxide (CdO) were successfully synthesized using
a solid-vapor deposition (SVD) for Cd and CdO powders in a horizontal quartz tube
furnace on p-type silicon substrates at temperature ranging from 1235 K to 1400 K with
argon and oxygen flows. Scanning electron microscopy (SEM) revealed that the CdO
morphology exhibited different structures of CdO on Si substrates, such as dendrite-like
petals, grass-like, microrods, and nanocrystalline thin films, via solid-vapor deposition
without a vacuum and catalyst under different parameters of growth. Moreover, the
structural, optical, and electrical properties of structures of CdO were studied and
investigated. The structures had an average crystallite size of 30 nm to 35 nm.
SEM also exhibited various shapes of CdO microstructures depending on the
position of Si substrates from the source material (CdO powder) in the furnace. The CdO
microstructures included microrods, microcubes, and grass packs-like. The structural and
optical properties of CdO microstructures were studied. The average crystallite size
decreased with an increase in the lattice constant when the distance of the substrates from
the source material during growth was increased.
CdO thin films were also deposited on p-type silicon and glass substrates at room
temperature using the thermal evaporation method for CdO powder in a vacuum. The Xray
diffraction (XRD) pattern showed that different structures of CdO were
polycrystalline in nature with a cubic structure using these methods in this study. Direct
band gap energy was 2.2 eV to 2.5 eV.
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Hall measurements revealed that the thin films of CdO were of n-type. The optical
direct band gap was decreased, whereas electrical conductivity and carrier concentration
increased after annealing at 500 °C for 1 h for CdO thin films were deposited on glass
substrates using thermal evaporation in vacuum.
These methods were used to fabricate n-CdO/p-Si solar cells due to the high
degree of roughness and the minimum effective reflectance obtained by deposition of n-
CdO thin films on p-type Si substrates. Moreover, the solar cell efficiency of the n-
CdO/p-Si was 5.51% under 100 mW/cm2 illumination conditions via the solid-vapor
deposition method while it was 5.92% using the thermal evaporation in a vacuum
method.
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Keywords
Growth And Characterization Of Cdo Structures , For Solar Cell Application