Browsing by Author "Kumarage, W.G.C."

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    Effects of NH3 concentration and annealing temperature on CBD CdS thin films
    (Postgraduate Institute of Science Research Congress, Sri Lanka, 2014) Kumarage, W.G.C.; Wijesundera, R.P.; Seneviratne, V.A.; Jayalath, C.P.; Dassanayake, B.S.
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    Influence of Bath Temperature on CBD-CdS Thin Films
    (ScienceDirect, 2016) Kumarage, W.G.C.; Wijesundera, R.P.; Seneviratne, V.A.; Jayalath, C.P.; Dassanayake, B.S.
    CdS thin films were grown on conducting glass substrates at different bath temperatures in order to investigate their influence on opto-electrical properties of the chemical bath deposited (CBD) CdS thin films. The CBD-CdS process was carried out with 0.001 M CdSO4, 0.002 M CS(NH2)2 and NH3 solution at different bath temperatures from 40 to 80 0C for one hour. Fabricated films were characterized using UV-Vis spectrometry, SEM, PEC cell and Profilometer. The optical transmittances of the films decreased with increasing bath temperature due to the increase of the film thickness. CdS cluster size of the thin films grown in the bath at a temperature of 60 0C was considerably larger compared to the films fabricated at other bath temperatures. The variation of optical band gap (Eg) was found to be in good agreement with cluster size variation while electrical characterizations reveal considerably high Voc and Isc values for the films fabricated at a bath temperature of 80 0C.
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    Tunable optoelectronic properties of CBD-CdS thin films via bath temperature alterations
    (2016) Kumarage, W.G.C.; Wijesundera, R.P.; Seneviratne, V.A.; Jayalath, C.P.; Dassanayake, B.S.
    The tunability of the band-gap value and electron affinity of the n-CdS by adjusting the growth parameters is very important as it paves the way to improve the efficiency of CdS-based solar cells by adjusting the band lineup with other p-type semiconductors. In this respect, polycrystalline n-CdS thin films were grown on FTO glass substrates at different bath temperatures (40–80 °C) by the chemical bath deposition technique. The structural, morphological and optoelectronic properties of CdS thin films were studied using x-ray diffraction, scanning electron microscopy, UV-Vis spectrometry, profilometry, atomic force microscopy, photoelectrochemical and Mott–Schottky measurements. Absorption measurements reveal that an energy-gap value of n-CdS can be adjusted from 2.27 to 2.57 eV and Mott–Schottky measurements indicate that the flat-band potential is increased from  −699 to  −835 V with respect to a Ag/AgCl electrode by decreasing the deposition bath temperature from 60 to 40 °C. This tunability of optoelectronic properties of n-CdS is very useful for applications in thin film solar cells and other devices.