Ultrafast time-resolved pump-probe (TRPP) apparatus has been applied to study the carrier dynamics of Si-doped InN thin films grown buffer by molecular beam expitaxy with and without a low-temperature growth GaN buffer layer. The peak of the PL has been found to increase from 0.7 to 0.8 eV with the back ground density. The total decay rates as a function of the delay time were obtained by the density-dependent TRPP peak intensity and the time-resolved TRPP signals. The total decay rates were interpreted as the sum of radiative and nonradiative recombination. The Shockley-Read-Hall decay rate derived from the TRPP signal at low photoexccitation density was found to increase with the doping density. At low concentration, the Auger recombination is not effective. The dominant recombination mechanism at room temperature is the Shockely-Read-Hall recombination.

The electro-optical properties of the ZnO/Si heterojunction embedded with self-assembled gold nanoparticles on patterned silicon substrate are investigated in this master thesis. High quality n-type ZnO film is deposited on patterned p-type silicon substrate by radio-frequency sputtering to form a ZnO/Si pn junction. The patterned silicon substrates are prepared by ICP-RIE using self-assembled nickel metal dot and silicon dioxide as etching mask. The optimum ICP process conditions of silicon nanopillars are CF4/Ar ~ 40/40 sccm and bias/RF power 400/400 W. Silicon nanopillars of diameter ~ 50 nm and height 100~400 nm are formed on the substrate surface. ZnO film is then deposited of a growth rate ~ 12 nm/min at the substrate temperature = 200oC. The plasmonic effects on the electro-optical properties, including photoluminescence (PL), reflection, and electrical characteristics, are studied by adding self-assembled gold nanoparticles within the ZnO film. The self-assembled gold nanoparticles are formed by thermal deposition and rapid thermal annealing at 700oC. The gold nanoparticles are observed by scanning electron microscopy (SEM) and particles of diameter about 100 nm. The PL intensity of ZnO is enhanced more than ten times at the peak wavelength = 380 nm by adding the gold nanoparticles and silicon nanopillars. Strong blue emission light could be saw with the naked eyes. For the electric characteristics, self-assembled gold nanoparticles in patterned ZnO/Si heterojunction show photoelectric conversion phenomenon because of high electromagnetic absorption and plasmonic effects.

Underwater communication is an important research of applied underwater acoustic since sound wave is the only effective way of transmitting messages under water. Underwater communication has always been a complicated problem especially in the shallow water environment due to the influence of multipath propagation. In the past, research on underwater communication had been done mostly by numerical simulation or laboratory experiments instead of doing in real oceanic areas. As a result, several research teams such as the Institute of Oceanography in Taiwan University, the Naval Research Laboratory and the acoustic laboratory of National Sun Yat-sen University Institute of Applied Marine Physics and Undersea Technology had executed a one-week real oceanic area experiment of underwater networking, communication, and acoustical tomography in Sizih Bay Marine Test Field. The experiment adopted 9 sets of underwater modem distributed within the range of 30 square kilometer to transmit, receive signals and collect CTD data. This research adopted part of the data gained from the experiment mentioned above to progress the feasibility test of acoustic tomography on current estimate to shallow water environment. By transmitting and receiving signals between stations, This research study the travel time difference between transmitting signals forward and backward caused by the flow field when using high frequency source in shallow water environment. This research estimated the average current speed and compared it to the weather buoy data from the Harbor and Marine Technology Center. This research discovered that most of the estimated results correspond to the weather buoy's ADCP data. Finally, this research adopted the method which does not require complex mathematics operation to estimate the two-dimensional flow field, and probe into what influence the angle between stations would bring to the deviation of estimating flow speed by using the Monte Carlo method.

The target of this work is to optically interconnect a semiconductor laser and a single mode fiber (SMF) through a simple Si bench technology using buried waveguide devices. This technology is suitable for applications such as optical transceivers and add-and-drop multiplexers. Three major components, namely, planarized laser diode, buried waveguide, and SMF are hybrid integrated on the Si bench. The ridge-type laser was planarized by BCB etch-back process, and was flip-chip mounted on the Si bench. On the other hand, the sol-gel buried waveguide was passively aligned to SMF using V-groove and U-groove techniques. Miss-alignment loss as low as 1 dB can be obtained.

Determination of Ca and P in foods and B, Si, P and S in steels by dynamic reaction cell inductively coupled plasma mass spectrometry

In this thesis, we study a series of Si doped InN films. These samples are grown on sapphire (0001) by molecular beam epitaxy (MBE). We have doped Si in InN films successfully. In this experiment, we control Si cell temperature to change carrier concentration of samples during InN film growth. The carrier concentration and mobility are explored by van der Pauw Hall measurement. As carrier concentration increases, mobility decreases. Carrier concentration changes with Si cell temperature from 6.16x1018 cm-3 to 1.19x1020 cm-3. Photoluminescence (PL) emission peak energy shows blue shift when carrier concentration increases, but the intensity decreases and full width at half maximum (FWHM) broadens. The PL peak of InN film with 1.19x1020 cm-3 split into two peaks 0.74 eV and 0.89 eV. In Raman spectra, Raman modes position and FWHM do not change with carrier concentration. In temperature dependence PL, the dependence of PL spectra shows decrease when carrier concentration increases. In power dependence PL, the PL emission peak energy of InN films with 6.16x1018 cm-3 and 8.50x1018 cm-3 show blue shift, while the PL peaks of InN films with 1.43x1019 cm-3 and 2.27x1019 cm-3 show no significant move. The fitting of power density vs. intensity is linear for all samples, but all slope of them are less than 1 expect for InN film with 1.43x1019 cm-3.

There were three poly-Si TFT made by ELA, SLS, and HREC. The HREC TFT had better reliability than ELA TFT and SLS TFT under AC and hot carrier stress. And the effect of bending in SLS TFT was more obvious then ELA TFT, it provide us a better choose to develop a flexible TFT LCD. In poly-Si TFT, the photon current would decrease if there was a grain boundary in the channel. In all parameters include both manufacture and measurement the HREC TFT had better behaviors than ELA TFT and SLS TFT. But there also some shortcomings we must overcome include we muse growth a heat-retaining layer extra and must etch it and the poly-Si/heat-retaining etch rate and so on.

In this study, silicon (Si) rich silicon dioxide (SiO2) films and terbium (Tb) embedded in three different Si containing films has been produced by e-beam evaporation and magnetron sputtering techniques. Post deposition annealing was done for different temperatures and durations to study its effect on both Si nanocrystal formation and Tb luminescence. It was verified by X-ray diffraction technique (XRD) that Si nanocrystals were formed in Si rich matrices. Energy dispersive X-ray (EDS) spectroscopy analysis was carried out to determine the relative concentrations of the atoms inside the produced films. X-ray photoelectron spectroscopy (XPS) gave the evidence of different bonding structures inside the Tb-Si-O containing films. Depth profile measurements were carried out to analyze changes in the relative concentration during sputtering of the layers after annealing of the Tb containing film. Luminescence characteristics of Si nanocrystals and Tb3+ ions were studied by photoluminescence (PL) spectroscopy. It was observed that Tb3+ luminescence enhanced by an energy transfer from Si nanocrystals and trap levels in a matrix. This result supplies valuable information about the excitation paths of Tb3+ ion the way of intense luminescence.

This thesis examines the luminescence properties of nanoscale silicon (Si) by using spectroscopic techniques. Since the development of new optical devices requires understanding light emission mechanism optical spectroscopy has become more important tool in the analysis of these structures. In this thesis, Si nanocrystals embedded in SiO2 matrix will be studied. Photoluminescence (PL) and Time-resolved photoluminescence spectroscopy (TRPL) have been used to detect the light emission in UV-Vis-NIR range. Experiments have been performed in the temperature range 10-300 K. PL is sensitive to impurities and defects that affect materials quality and device performance. In this context, the role of defects in limiting the luminescence of Si nanocrystals and the removal of these defects by hydrogen passivation has been investigated. v TRPL was employed to determine the time evolution of photoluminescence as function of temperature. The decay time of the PL spectra was determined by a stretched exponential function and perfectly fitted to an expression based on three excitonic levels. Carrier lifetimes associated with these three levels were determined and compared with literature. Additionally, temporal variation of PL from free-standing Si nanoparticles is studied under a strong laser illumination. The observed bleaching behavior (time dependent emission intensity), which is reversible, have discussed in terms of exciton trapping at the interface between nanocrystal and the surrounding oxide layer. The results of this thesis will provide new insight on the understanding of light emission mechanism of Si nanocrytals.

In this thesis, a switched-current sigma-delta modulator (SDM) with op-amp active integrator is proposed. The major study is focused on using the op-amp to reduce the input impedance for high speed and high solution and utilizes the dummy switch to decrease the clock feedthrough (CFT) error. We use a sample-and-hold circuit which consists of an op-amp active memory cell and a dummy switch circuit to implement the integrator. It is applied to the building blocks of SDM. The modulator is a second order sigma-delta modulator. A current comparator transforms the current signal into digital voltage signal. A single-bit digital-to-analog (D/A) feedback circuit is used to convert the one-bit digital output to the SI integrator .The modulator is designed in the current mode technique. The delta-sigma modulator simulates using the parameters of the TSMC 0.35£gm CMOS process. The simulation results show that the signal to noise plus distortion ratio (SNDR) is 72 dB, the sampling rate is 10.24MHz, the oversampling ratio is 128, the power consumption is 21mW, the dynamic range is about 70dB, and the power supply is 3.3V. Furthermore, the circuit is verified by cadence-hspice simulation.