Li-Zen Hsieh

Growth Evolution of ZrO2 from Deposited Zr Metal during Thermal Oxidation

This work reveals how oxidation temperature affects the diffusion of Zr, the reaction behavior of oxygen and silicon atoms in the interior stacked layer structure and the corresponding crystalline phase of oxide. The depth distributions of the three important inclusive atoms Zr, O, and Si are experimentally determined.

Hysteresis in gadolinium oxide metal-oxide-semiconductor capacitors

This investigation explores how oxidation affects the gadolinium oxide capacitor and the corresponding Gd2O3 hysteresis phenomenon. The current-voltage varied with Gd2O3 thickness and a charged capacitance voltage (C-V) curve with a left shift is also observed in experimental results. The breakdown voltages rise with increasing oxidation time, while the corresponding C-V hysteresis gaps decrease with increasing oxidation time.

Fabrication of a far-infrared photodetector based on InAs/GaAs quantum-dot superlattices

A far-infrared photodetector based on twenty layers of self- assembled InAs/GaAs quantum dot superlattices is fabricated. Measure- ments by Fourier-transform infrared spectroscopy at 77 K reveal that the response of the device is in the range of 9 to 16.3 mm, with a peak absorption wavelength near 13.2 mm (756 cm 21 ). The electrical charac- teristic of the devices current-voltage response is 63 m Aa t21-V bias voltage when a 1-cd light source is at 15-cm distance.

Comparative analysis of platinum diffusion parameters in GaAs and GaN semiconductors

The phenomena of platinum (Pt) atoms diffused thermally into n-type GaAs and GaN compound semiconductors have been unveiled. Although the diffusion of Pt into silicon as a carrier lifetime reducer and leakage current minimizer has already been detailed, Pt diffusion into III-V semiconductor has remained unknown. In this study, Pt was surface coated and thermally diffused into (driven-in) GaAs and GaN samples under the temperature range of 500–900°C. The corresponding diffusion constants and diffusion energies were then determined. Different luminescence spectra were observed and analyzed. Among diffused samples, Pt was found to be a shallow donor in GaN semiconductor, but alternatively found as a deep acceptor for Pt-diffused GaAs samples.

Palladium Diffusion Transport in n-Type GaAs

The aim of this study is to determine the diffusion coefficient of palladium (Pd) in gallium arsenide under different annealing conditions. The extent of diffusion was characterized using the secondary ion mass spectrometry (SIMS) technique. The temperature-dependent diffusion coefficients of Pd are 8.4×10-13, 2.25×10-12, and 9.51×10-12 cm2/s, respectively, at temperatures of 400, 550, and 850 °C. The Pd diffusion constant and activation energy in GaAs are calculated as 3.54×10-10 cm2/s and 0.35 eV, respectively. This indicates that the major diffusion mechanism of Pd in GaAs is interstitial diffusion.

Enhanced modulation rate in platinum-diffused resonant-cavity light-emitting diodes

This study is focused on the modulation response of resonant-cavity light-emitting diodes (RCLEDs). Platinum (Pt) atoms are diffused into the 660nm RCLED epitaxial layers to increase the concentration of recombination centers and to improve the modulation speed. The RCLED has an AlInGaP multi-quantum-well active layer which was embedded into AlGaAs-distributed Bragg reflectors to form a one-wavelength (1-λ) optical resonator. Afterwards, the deep-level Pt impurity was diffused into the RCLED and an improved average rise time, from 18.07to12.21ns, was obtained. The corresponding modulation frequency can be increased from 19.54to30.21MHz.

Kinetic analysis of antibody-antigen interactions using phase-detection-based surface plasmon resonance sensor system

Surface plasmon resonance (SPR) biosensors have the advantage of being highly sensitive, requiring no fluorescent-labeled analytes or receptors, and being capable of monitoring molecular interactions in real time. Thus, they have been widely used in determining the dynamics of molecular interactions. However, owing to the lack of experience in employing phase-detected SPR, there have been no research reports on the determination of affinity constant for antigen–antibody interactions. In this study, we used a custom-made phase-detection SPR sensor system to investigate the kinetic parameters of an antibody binding to an antigen immobilized on a CM5 sensor chip. This system provided real-time measurements of molecular interactions on the sensor chip. The association and dissociation rate constants and the corresponding affinity were obtained.

Study of AlGaInP multiquantum-well/double heterostructure light-emitting diodes with In-added GaP window layer regrown by antimony-based liquid phase epitaxy

The characteristics of surface-emitting AlGaInP multiquantum-well (MQW) and double heterostructure (DH) light-emitting diodes (LEDs) with a GaP window layer regrown by a GaP source melt with the addition of indium in the liquid phase epitaxy (LPE) system are studied. Using antimony in the source melt instead of gallium eliminates the phenomenon of melt back at the top layer of the LED during the LPE regrowth process. Meanwhile, adding In and Zn to the source melt significantly increases the GaP growth rate and effectively reduces residual melt during the regrowth process. Thus, the AlGaInP LED with a Zn-doped GaP window layer regrown by In being added, Sb-based LPE exhibits a lower turn-on voltage and higher light output power than that without the regrown GaP window layer. However, the emission peak wavelength of the MQW LED shifts a little after the LPE regrowth process. The DH LED does not shift. Thus, the DH structure is more suitable than the MQW structure for the LPE regrowth process of GaP.

Temperature Characteristics of High Modulation Rate Platinum-Diffused AlGaInP Resonant-Cavity Light-Emitting Diodes

This study is focused on the temperature characteristics of platinum-diffused AlGaInP resonant-cavity light-emitting diodes (RCLED). The shape of the platinum-diffused AlGaInP RCLED emission spectra and the full width at half maximum (FWHM) of the main electroluminescent (EL) spectra are almost uninfluenced over the measured temperature range of 20 to 100 ?C. Therefore, the platinum-diffused devices show a high characteristic temperature, and a small temperature shift in the peak emission wavelength.

Oxygen and Hydrogen Implanted Oxidation Enhancement of Al0.98Ga0.02As/Al0.7Ga0.3As Distributed Bragg Reflector Structure

This study investigates the lateral oxidation enhancement of Al0.98Ga0.02As/Al0.7Ga0.3As distributed Bragg reflector (DBR) structure layers implanted with either oxygen or hydrogen ions. The results revealed that the lateral oxidation rate of Al0.98Ga0.02As/Al0.7Ga0.3As DBR layers with oxygen-implantation was higher than that in the case without oxygen-implantation, but hydrogen implantation in Al0.98Ga0.02As/Al0.7Ga0.3As DBR layers did not lead to an oxidation enhancement phenomenon. A high oxidation rate can shorten the oxidation time or lower the oxidation temperature, and thus would aid in increasing DBR performance and reliability.