Physics

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Start date: 1990End date: 1999

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Now showing 1 - 10 of 44
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    Spectral responses of electrodeposited cuprous oxide thin film electrodes
    (Natural Resources, Energy and Science Authority of Sri Lanka, 1995) Siripala, W.
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    ITO/n-Cu2O/p-CuxS Thin Film Solar Cell
    (Sri Lanka Association for the Advancement of Science, 1997) Perera, L.D.R.D.; Wijesundera, R.P.; Siripala, W.; Jayasuriya, K.D.; de Silva, K.T.L.; Jayanetti, J.K.D.S.
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    Ozone Production by Pulsed power in Dry Air
    (12th IEEE International Pulsed Power Conference, 1999) Samaranayake W J M; Miyahara Y; Namihira T; Katsuki S
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    Characteristics of Ozone Production by Pulsed Power
    (12th IEEE International Pulsed Power Conference, 1999) Samaranayake, W.J.M.; Miyahara, Y.; Katsuki, S.; Lisitsyn I; Hackam, R.; Akiyama, H.
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    A Study of CuInS2 Thin Films for Photovoltaic Applications
    (Proceedings of the Technical Session of Institute of Physics, 1999) Wijesundera, R.P.; Nadesalingam, M.P.; Siripala, W.; Jayasuriya, K.D.; Kalingamudali, S.R.D.; Jayanetti, J.K.D.S.; de Silva, K.T.L.
    Thin films of copper indium disulphide (CuInS2) on Ti Substrate were prepared by annealing potentiastatically electrodeposited Cu-In alloy in H2S gas at 5500 C. Films were characteristised by X-ray diffraction (XRD), scanning electron microscopy (SEM), and spectral response in a polysulphide electrolyte. XRD measurements revealed the formation of the polysrystaline CuInS2 thin films and the abscence of any other phases. SEM showed the formation of crystallites having the size about 0.2 ?m. Variations of spectral response, open-circuit voltage (Voc) and short circuit current (Isc) with annealing in air have been studied. As deposited CuInS2 films exhibit a direct band gap of 1.5 eV, and shows n-type behaviour when used in a Photoelectrochemical (PEC) cell. Heat treatment shows a considerable enhancement of the photoresponse.
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    Growth and Characterization of Copper Indium Diselenide
    (Proceedings of the Technical Session of Institute of Physics, Sri Lanka, 1996) Chithrani, B.D.; de Silva, K.T.L.; Jayanetti, J.K.D.S.; Siripala, W.
    CuInSe2 thin films were prepared on Ti plates by electrodeposition from an aqueous solution containing CuCl2, InCl3 and SeO2. The deposition was carried out at -0.5V Vs SCE. X-ray diffraction and Scanning electron microscopy have been used to study the crystallographic and morphological properties of the samples. Effects of annealing in air have also been monitored. Apparent bulk structure changes have been observed during annealing. Annealing of films at 350 0C was found to result in the formation of CuInSe2 films having a chalcopyrite structure, indicating that the samples are of good quality.
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    Computational Study of I-V characteristics of ITO/Cu2 O/Metal junctions, Technical Session of Institute of Physics
    (Processing of the Technical Session of Institute of Physics, 1999) Wijesinghe, W.M.P.L.; Siripala, W.; Jayasuriya, K.D.; Kalingamudali, S.R.D.
    A theoretical model for current-voltage (I-V) characteristics of back-to-back diode systems was developed using the ideal diode equation. A computer model was developed using the language C++ to fit the experimental data to the theoretical equation and to determine the ideality factors and reverse saturation currents of each diode. This model was tested with commercial back-to-back diode systems. The values obtained for the above parameters from the theoretical fits were in very good agreement with the standard values. The experimental I-V characteristics data obtained for fabricated ITO/Cu2O/Metal (Au, Ag and Hg) structures were fitted to the model and values for the relevent parameters were obtained. These values indicate that the fabricated systems are back to back diodes except the ITO//Cu2O/Hg structure. Using this model, a good understanding of I-V characteristics of metal-semiconductor-metal diodes can be gained and thereby the quality of junction devices can be tested.
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    Optical Design and Performance of the SASP Spectormeter at TRIUMF
    (Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1999) Walden, P.L.; Walton, T.G.; Miller, C.A.; Yen, S.; Abegg, R.; Auld, E.G.; Campbell, J.R.; Chakhalyan, J.; Churchman, R.; Duncan, F.; Falk, W.R.; Frekers, D.; Green, A.; Green, P.E.W.; Hartig, M.; Hausser, O.; Haddock, C.; Hicks, K.; Hutccheon, D.; Jones, G.; Korkmaz, Y.Ke.E.J.; Khan, N.; Ling, A.; Lobb, D.E.; Naqvi, S.I.H.; Olsen, W.C.; Opper, A.; Otter, A.; Punyasena, M.A.; Reeve, P.; Zhao, J.
    A new Q?Q-Clamshell magnetic spectrometer called SASP has been commissioned in the proton hall at TRIUMF. The principal optical characteristics are: a solid angle acceptance of 13.5 msr, a momentum bite of 25%, a momentum resolution of ?p/p=2?10?4, and a maximum central momentum of 720 MeV/c. We describe the optical design, the magnetostatic design, the magnetic field mapping procedure, and the performance of this instrument.
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    Surface States at CuInSe2/Aqueous Electrolyte Interface
    (Journal of Science of the University of Kelaniya Sri Lanka, 1997) Siripala W
    Impedance measurements were used to evaluate the relative band edge positions of single crystal p-CuInSej electrodes in aqueous 0.1M IQS04 solution by measuring die extrapolated flat-band potentials, Vf t . We find that Vf t can be shifted by oxidation and reduction of the electrode surface and this observation was verified by chopped light current-potentialmeasurements. The surface state density distribution responsible for this shift was evaluated and found that it islocated at 0.43 eV above the valence band with a peak density of 3x101 4 eV'1 cm' 2 and it could be removed by electrochemical reduction
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    Investigation of the 12C(p,d,pi+)11B Reaction in the Quasifree Region
    (Physical Review C, 1998) Benjamintz, M.; Falk, W.R.; Auld, E.G.; Campbell, J.R.; Green, A.; Korkmaz, E.; Ling, A.G.; Punyasena, M.A.; Roos, P.G.; Walden, P.L.; Yen, S.
    12C(p? ,d?+)11B has been investigated in the quasifree region at energies of 370 and 500 MeV. For each energy, measurements were made at the four angle combinations of (?d,left,??,right) equal to (15�, 30�), (15�, 55�), (25�, 30�), and (25�, 55�). In addition to strong excitation of the g.s. 3/2- state, the 2.12 MeV 1/2- and 5.02 MeV 3/2- states are also excited with appreciable strength. Furthermore, a broad continuum at an excitation energy of about 20 MeV, corresponding to the 1s1/2 hole state is prominently seen. The pion differential cross section distributions exhibit maxima when the recoil nucleus momenta are at a minimum. Analyzing powers were obtained over the range of pion energies investigated. Several measurements for the 2H(p? ,d?+)n reaction are also reported. The results are compared with plane-wave impulse approximation and distorted-wave impulse approximation calculations