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Rayleigh surface acoustic wave (SAW) devices based on 128° YX LiNbO3 and ZnO/Si substrates with different resonant frequencies from ∼62 MHz to ∼275MHz were fabricated and characterized. Effects of SAW frequency and power on microfluidic performance (including streaming, pumping, and jetting) were investigated. SAW excitation frequency influenced the SAW attenuation length and hence the acoustic energy absorbed by the liquid. At higher frequencies (e.g., above 100 MHz), the SAW dissipated into liquid decays more rapidly with much shorter decay lengths. Increasing the radio frequency (RF) frequencies of the devices resulted in an increased power threshold for streaming, pumping, and especially jetting, which is attributed to an increased absorption rate of acoustic wave energy. ZnO SAW devices could achieve similar streaming, pumping, and jetting effects as well as frequency effect, although the SAW signals are relatively weaker. [ABSTRACT FROM AUTHOR]

To enable optimum network transmission, the ideal is to launch as high laser power as possible into the optical fiber, to overcome the effects of fiber attenuation and maintain an acceptable signal to noise ratio. Launching high powers into a fiber however, results in unwanted nonlinear effects. Stimulated Brillouin scattering (SBS) is one of the nonlinear effects which reflects a significant proportion of the transmitted optical power back to the transmitter, degrading the system severely. This paper reports the development of a digitally selected supermode distributed Bragg reflector monolithic laser chip which can provide significant linewidth broadening using a pure frequency modulation technique by application of a dither current. By modifying a small segment of the laser chip material refractive index, it produces a modulation of the longitudinal mode and hence laser frequency; the monolithic laser chip has reduced the effects of SBS significantly with very little parasitic amplitude modulation. [ABSTRACT FROM AUTHOR]

ZnO thin film based surface acoustic wave (SAW) devices have been utilized to fabricate microfluidic pumps. The SAW devices were fabricated on nanocrystalline ZnO piezoelectric thin films deposited on Si substrates using rf magnetron sputtering and use a Sezawa wave mode for effective droplet motion. The as-deposited ZnO surface is hydrophilic, with a water contact angle of ∼75°, which prevents droplet pumping. Therefore, the ZnO surface was coated using a self-assembled monolayer of octadecyltrichlorosilane which forms a hydrophobic surface with a water contact angle of ∼110°. Liquid droplets between 0.5 and 1 μl in volume were successfully pumped on the hydrophobic ZnO surface at velocities up to 1 cm s-1. Under acoustic pressure, the water droplet on an hydrophilic surface becomes deformed, and the asymmetry in the contact angle at the trailing and leading edges allow the force acting upon the droplet to be calculated. These forces, which increase with input voltage above a threshold level, are found to be in the range of ∼100 μN. A pulsed rf signal has also been used to demonstrate precision manipulation of the liquid droplets. Furthermore, a SAW device structure is demonstrated in which the ZnO piezoelectric only exists under the input and output transducers. This structure still permits pumping, while avoiding direct contact between the piezoelectric material and the fluid. This is of particular importance for biological laboratory-on-a-chip applications. [ABSTRACT FROM AUTHOR]

Presents a study which investigated the effects of growth temperature and subsequent annealing temperatures on the electrical properties of the low temperature grown gallium arsenide. Background on the sample material; Description of the experimental setup; Results.

Presents a study that compared the radiation resistance of electron irradiated indium phosphide grown by metal-organic chemical-vapor deposition and liquid encapsulated Czochralski. Experimental procedure; Results; Discussion.

Discusses a study which investigated the effect of growth temperature on the electrical properties of AlInAs/InP grown by molecular beam epitaxy and metal-organic chemical vapor deposition. Techniques used for the growth of the layers on n[sup+]-InP substrates; Characteristics of the layers; Condition in which Schottky barrier heights decreases.

Provides information on a study that analyzed the effects of 1 MeV electron radiation on the I-V properties of p-type InP Schottky diodes. Sample preparation and radiation; Results and discussion on the study.

Presents an analysis of current-voltage, capacitance-voltage properties of ITO/p-InP solar cell structures. I-V and C-V characteristics of ITO/InP diodes; Analysis of reverse bias I-V properties; Discussion on I-V, C-V properties after ITO removal.

Reports the quantum Hall effect of electrons in AlGaAs/Ga[sub1-x]In[subx]As/gallium arsenide pseudomorphic strained heterostructures. Effect of strain in the GaInAs layer; Overview of reciprocal magnetic fields corresponding to the maximum of magnetoresistivity; Number of scattering events by cluster-scattering centers in one orbit area.