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A numerical model is developed based on the modified mild-slope equation. It takes into account the effects of reclamation, navigating ships, bottom topography and its friction, coastal reflectivity, ocean swell and wind. After calibration with the field wave assessment data, it is applied to predict the wave climate with the 1996 reclamation scenario and the corresponding ship navigation data. The predicted results are satisfactory. The present model would be useful to assess the environmental impact of future port and marine works on harbour waves and ta assist in planning future navigation, port and other marine facilities In Hang Kong waters.

In order to obtain low threshold VCSELs high reflectivity mirrors are crucial in their designs. Typically used Distribute Bragg Reflectors (DBR) provide reflectivity over 99.8% in the spectral range of 70 nm. To achieve polarization control numerous of shallow etchings approaches has been proposed but already lastly developed High Contrast Grating (HCG) has an ability to discard one of the mode polarization completely and additionally to provide twice broader spectrum of large reflectivity. We present simulation results of various HCG structures based on Si and GaAs high index materials combined with SiO2 and AlOx cladding low index material layers respectively. Reflectivity simulations at 980nm wavelength show that reflectivity exceeding 99.8% can be obtained in a broad range of grating parameters. Additionally the same parameters assure very strong discrimination between TE and TM modes. Manufacturing process of a grating might involve undesirable imperfections leading to deterioration of optical properties of HCG. Hence we consider error analysis assuming random nonperiodicity of a grating structure based on Gaussian distribution of manufacture inaccuracy with standard deviation as inaccuracy measure varying from 0 nm to 50 nm. We found that inaccuracy in the range 0 nm-25 nm does not deteriorates significantly the reflection of HCG.

Among methods modeling electronic structures of low dimensional heterostructures, such as first principles, tight binding, k·p, etc., the multiband k·p method is the most effective for low dimensional systems with a big compilation of atoms such as quantum dots. Numerical implementation like the finite difference method and the finite element method engages differential or integral process and thus requires a 3D-space mesh. In our developed Fourier transform-based k·p method (FTM), both Hamiltonian matrix and envelope functions are formulated in Fourier domain. The analytical Fourier transform of the 3D shape function of the object can be adopted such that meshing 3D space is avoidable in retrieving eigen solutions of k·p equations. Both the kinetic part and the strain have been incorporated in the Hamiltonian equation. The FTM demonstrates advantage on controlling spurious solutions due to its inborn cut-off process, whereas incorporation of Burt-Foreman operator ordering further enhances the merit.

Nanostructures have been attracted great attentation for many years due to their novel properties and advantages associated with the scale. In this plenary talk, I will present the artificial nanostructures and devices developed in our group. I will also discuss their applications in light source, light manipulation and high resolution imaging for next generation photonic technology.

Indium antimonide (InSb) has the smallest energy gap in the binary III-V materials, with a cut off wavelength of 7 μm at 300 K. The introduction of nitrogen into InSb causes a phenomenon of a strong negative band gap bowing effect, leading to the extended response wavelength of 8 μm to 12 μm range, which provides an alternative for long wavelength infrared photodetection. In this Supplementary Equipment Project for development of InSbN alloys for 8 to 12 micron room temperature infrared photodetectors, we are granted funding for buying some InSb wafers and an Infrared laser. The InSb wafers are used for formation of InSbN alloys by ion implantation of nitrogen and the laser is used for optical characterization. As planned, we have fabricated InSbN alloys by ion implantation under different conditions and characterized them accordingly. In this report, we attempt to show what happen when nitrogen is incorporated to the InSb material. The fabrication, structure, electrical, and band gap properties of InSbN are presented. A thin layer of InSb1-xNx has been fabricated by nitrogen implantation in the near-surface region of the InSb wafers. Hall measurement shows that higher annealing temperature will result in lower carrier concentrations and stronger metallic properties. X-ray photoelectron spectroscopy indicates the formation of oxides including In2O3 and Sb2Ox. When the implanted impurities increase, less percent of them will occupy the anion lattice sites, but the total substitutional nitrogen atoms still steadily increase. Photocurrent measurements prove the bandgap reduction and the existence of negative bandgap. The diffusion behavior of implanted nitrogen in InSb has been ATTENTION: The Singapore Copyright Act applies to the use of this document. Nanyang Technological University Library 3 studied by SIMS. A strong movement of nitrogen towards the sample surface was observed. The nitrogen concentration peaks are found linearly shifted to the deep region position with the annealing time and temperature. Diffusion coefficients at various temperatures are plotted. The corresponding activation energy for nitrogen in InSb is found to be 0.55eV.

We investigated the influence of thermal interdiffusion on the band structures of Si1−xGex /Si single quantum wells SQWs with a well width of 125 Å and Ge concentration x=0.3. Rapid thermal annealing with the temperatures of 750 and 800 °C leads to substantial interdiffusion indicated by a significant photoluminescence PL blueshift as large as 46 meV. The effect is modeled by a Si–Ge atomic interdiffusion at the heterointerface. The band structures and optical transitions of QW after interdiffusion were calculated based on an error function distribution and the 6+2-band k· p method. The diffusion lengths of the intermixing process are deduced from the PL shift. The thermal dependence of the interdiffusion coefficients follows the Arrhenius law. An activation energy Ea for interdiffusion of 2.75 eV is obtained. Our investigation indicates that the 6+2-band k· p formalism is valid for interdiffused Si1−xGex/Si QWs. Published version

The development of copper metallization for deep submicron integrated circuits (DSICs) was a project jointly funded by the Ministry of Education (MoE) and the Agency for Science Technology and Research (A*STAR). Being a very broad based project, the report is deliberately divided into 3 parts. Each part is a complete report by itself - complete with summary, table of contents and various chapters. The 3 parts are identified as follows

The quantum well intermixing (QWI) technique using pulsed-photoabsorption-induced disordering (P-PAID) in the InGaAs/InGaAsP material system has been investigated. RGM 14/99

This project aimed (1) to establish the relationship between the processing parameters involved in rapid thermal annealing (RTA) and anodic oxide induced intermixing (AOII) and material properties of semiconductor epitaxial layers, and (2) to establish the relationship between the processing parameters involved in RTA and AOII and device performance of LEDs and laser diodes. RG 5/99

In this project, quaternary GaInAsP materials grown on GaAs and InP substrates are systematically characterized. GaInAs/A1GaAs and GaInAsP/InP multuple quantum well structures grown on GaAs and on InP substrates, respectively, are investigated. Quantum well infrared photodector devices made up of these two kinds are fabricated. RG 27/98