It represents a viable solution for the realization of a portable biosensor platform that could screen/diagnose acute
myocardial infarction by measuring cardiac marker concentrations such as cardiac troponin I (cTnI), creatine kinase MB
(CK-MB), and myoglobin (MYO) for application to u-health monitoring system. The portable biosensor platform
introduced in this presentation has a more compact structure and a much higher measuring resolution than a conventional
spectrometer system. Portable guided-mode resonance (GMR) biosensor platform was composed of a biosensor chip
stage, an optical pick-up module, and a data display panel. Disposable plastic GMR biosensor chips with nano-grating
patterns were fabricated by injection–molding. Whole blood filtration and label-free immunoassay were performed on
these single chips, automatically. Optical pick-up module was fabricated by using the miniaturized bulk optics and the
interconnecting optical fibers and a tunable VCSEL (vertical cavity surface emitting laser). The reflectance spectrum
from the GMR biosensor was measured by the optical pick-up module. Cardiac markers in human serum with
concentrations less than 0.1ng/mL were analyzed using a GMR biosensor. Analysis time was 30min, which is short
enough to meet clinical requirements. Our results show that the GMR biosensor will be very useful in developing lowcost
portable biosensors that can screen for cardiac diseases.
Micro-disk resonators were fabricated using Er doped silicon-rich silicon nitride (SRSN:Er). SRSN:Er thin films are fully CMOS-compatible and show efficient Er3+ luminescence pumped off-resonantly via Si nanoclusters. The high refractive index of SRSN (>2.0 at 1.5 μm) allows freedom in designing compact micro-disk resonators. Micro-disks with two different contents of Er (0.2 at.%, 0.02 at.%) with a diameter of 25 μm were fabricated, and characterized using evanescent coupling using tapered fibers. Whispering gallery modes with Q-factors in excess of 13000 were obtained, and FDTD calculations indicate that much higher values should be possible. Finally, we demonstrate excitation of fundamental whispering gallery mode via off-resonant, top-pumping of the SRSN microdisk.
An electrically driven light emission from silicon is a long-standing problem in silicon photonics. Recently, significant progress has been made using silicon quantum dots embedded in silicon nitride thin films, transparent doping layers and electrodes, and surface modified structures. This paper provides an overview of progress in the device physics and fabrications of the nanocrystal silicon light emitting diodes including new device structures to improve the light extraction efficiency as well as highlights in growth of silicon quantum dots and their quantum confinement effects.
Organic light-emitting diode (OLED) has a good candidate for next generation flat panel display (FPD). However, it is very difficult to fabricate high performance OLEDs on plastic substrate because its mechanical and thermal properties are very poor. Before the ITO deposition, we used a new plasma treatment for good contact with ITO and PES. PES substrate is stayed in vacuum above 12 hours to reduce humidity and unknown chemical gas.
We successfully fabricate OLED on PES substrate using PLD-ITO anodes. We can observe more uniform and bright emission image from the OLED and fix the optimum conditions for fabrication process for OLED. Maximum electro luminescence (EL) and current density at a 100 cd/m<sup>2</sup> are 2500 cd/m<sup>2</sup>, 2mA/cm<sup>2</sup>, respectively and external quantum efficiency of OLED is about a 2.0%.
Nanocrystal Si (nc-Si) sensitization of Er in a silica matrix to obtain high optical activity in a Si-compatible material is investigated. Er-doped silicon-rich silicon oxide (SRSO) films, which consist of nc-Si embedded inside an SiO<sub>2</sub> matrix, were deposited by electron-cyclotron resonance plasma enhanced chemical vapor deposition (ECR-PECVD) using SiH<sub>4</sub> and O<sub>2</sub> with concurrent sputtering of Er followed by a high temperature anneal. For comparison, Er-free SRSO films were also deposited. Detailed investigation of processing conditions indicates that an annealing process consisting of 30 min anneal at 950°C without hydrogenation to be optimum for activation of Er. Investigation of MOS diode structure with Er-doped and Er-free SRSO films indicates that a mesa-type structure with n<sup>+</sup> poly-silicon top contact, p-type substrate, and SRSO Si content of less than 40% gives the best diode performance. Er-free SRSO diodes fabricated using the optimum conditions show electroluminescence under forward bias. Er-doped SRSO diodes show photoresponse at 1.54 μm due to nanocrystal -- Er interactions, showing the promise of developing integrated, Si-based 1.54 μm light detectors for integrated microphotonic devices.
The role of the size of amorphous silicon quantum dots in the Er luminescence at 1.54 µm was investigated. As the dot size was increased, the more Er ions were located near one dot due to its large surface area and more Er ions interacted with other Er ions. This Er-Er interaction caused a weak photoluminescence intensity despite the increase in the effective excitation cross section. The critical dot size, needed to take advantage of the positive effect on Er luminescence, is considered to be about 2.0 nm, below which a small dot is very effective in the efficient luminescence of Er. However, the hydrogenation is considered to suppress this Er-Er interaction.
The microstrip filters, such as multipole lowpass filter and multipole bandpass filter, have been designed, fabricated, and characterized. The YBa<SUB>2</SUB>Cu<SUB>3</SUB>O<SUB>7-(delta</SUB> ) (YBCO) epitaxial thin films on MgO substrates were grown in situ at 760 degree(s)C by pulsed laser deposition. The design of filters in a microstrip configuration and their microwave responses were simulated by microwave design simulator, respectively. The filter patterns on the laser ablated YBCO/MgO film were generated using conventional photolithography and ECR-etching process. The performance of filters was measured as a function of temperature and frequency. Microwave loss properties were superior for the filters patterned from HTS films to the filters fabricated from Au-metal films of the same dimensions.