Chua Choon Ling

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ZnO nanorod arrays were fabricated using a hydrothermal method. The nanorods were studied by scanning electron microscopy, photoluminescence (PL), time-resolved PL, X-ray photoelectron spectroscopy, and positron annihilation spectroscopy before and after annealing in different environments and at different temperatures. Annealing atmosphere and temperature(More)
N-type 6H-SiC samples irradiated with electrons having energies of E(e)=0.2, 0.3, 0.5, and 1.7 were studied by deep level transient technique. No deep level was detected at below 0.2 MeV irradiation energy while for E(e)>/=0.3 MeV, deep levels ED1, E(1)/E(2), and E(i) appeared. By considering the minimum energy required to displace the C atom or the Si atom(More)
This study determined the optimum ratio of contaminated soil to sewage sludge (organic amendments) in enhancing the biodegradation of refinery oil sludge. It also evaluated the treatment efficiency of refinery oil sludge by composting and the effect of sewage sludge addition on the biodegradation of refinery oil sludge. Experiments were conducted in six(More)
Investigation on the room-temperature ultraviolet lasing characteristics of a single ZnS microbelt laser is presented. Lasing emission with peak wavelength at round 335 nm is observed from the hexagonal-wurtzite phase of ZnS microbelt under optical excitation. This is due to the Fabry-Perot resonance along the length of the microbelt. By studying the(More)
Zinc oxide (ZnO) is an interesting and promising semiconductor material for many potential applications, e.g. in opto-electronics and for sensor devices. However, its p-type doping represents a challenging problem, and the physical reasons of its mostly n-type conductivity are not perfectly clear at present. Efforts to achieve p-type conductivity by ion(More)
Using a monoenergetic positron beam, annealing study of the Al/n-GaSb system was performed by monitoring the Doppler broadening of the annihilation radiation as a function of the positron implanting energy. The S-parameter against positron energy data was successfully fitted by a three-layer model (Al/interface/GaSb). The annealing out of the open volume(More)
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