Browsing by Author "Leung, S"

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    The measurement of minority carrier diffusion lengths for high purity GaAs using an electron beam induced current technique
    (Australian Nuclear Science and Technology Organisation, 1990-07) Butcher, KSA; Alexiev, D; Tansley, TL; Leung, S
    Measurements of minority carrier diffusion lengths for p-type and n-type GaAs were carried out using an electron beam induced current technique. The GaAs material was grown by liquid phase epitaxy at the Australian Nuclear Science and Technology Organisation. The diffusion lengths measured for the n-type materials show good agreement with past results for material of similar purity. For higher purity p-type and n-type samples diffusion lengths were observed which are larger than any previously reported. For different electron beam voltages the observed values of diffusion length were unaffected by surface recombination. This again indicates very pure material. The diffusion length measurements reported here indicate that the LPE GaAs samples being produced by the Australian Nuclear Science and Technology Organisation's Radiation Detectors Project are of the highest quality for producing X-rays and low energy gamma ray radiation detectors.
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    The world's smallest gas cylinders?
    (American Association for the Advancement of Science (AAAS), 1997-08-15) Gadd, GE; Blackford, MG; Moricca, SA; Webb, N; Evans, PJ; Smith, AM; Jacobsen, GE; Leung, S; Day, A; Hua, Q
    Argon gas was trapped at high pressure within hollow carbon tubes grown in vapor that have an outer diameter of between 20 and 150 nanometers. The gas was forced into the tubes by hot isostatically pressing (HIPing) the carbon material for 48 hours at 650°C under an argon pressure of 170 megapascals. Energy dispersive x-ray spectroscopy maps and line scans across the tubes show that the argon is trapped inside the bore and not in the tube walls. The room temperature argon pressure in these tubes was estimated to be about 60 megapascals, which indicates that equilibrium pressure was attained within the tubes at the HIPing temperature. These findings demonstrate the potential for storing gases in such carbon structures. © 1997 American Association for the Advancement of Science