Publisher: C. C. Yang Editors: Jui-che Tsai, Hsiao-wen Lin Feb. 28, 2006 | |||||||||||||||||||||||
News Activity Special Report Visiting Professor Profiles Laboratory Descriptions |
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New faculty members of the Graduate Institute of Electro-Optical Engineering∼ Three professors joined our Institute since February 1st, 2006. Below is a short introduction to their experiences and expertise.
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Workshop on Photonic Crystals and Nano-Photonics Time: November 4th , 2005 (afternoon) and November 5th, 2005 (all-day) Place: Room 101, Barry Lam Hall, National Taiwan University About the Workshop The Workshop on Photonic Crystals and Nano-Photonics was held from November 4th (afternoon) to the 5th (all-day) at Room 101, Barry Lam Hall, NTU. Sponsored by Japan’s IEICE (The Institute of Electronics, Information and Communication Engineers), two internationally renowned speakers, Dr. Kiyotoshi Yasumoto (Department of Computer Science and Communication Engineering, Kyushu University, Fukuoka, Japan) and Dr. Masaya Notomi (Photonic Nanostructure Research Group, NTT Basic Research Laboratories, Atsugi, Japan), were invited to lecture on special topics. Moreover, 14 local scholars and experts of related fields presented their outstanding research results. Participants to the workshop had been originally estimated to be around 150. With the enthusiastic participation from all fields, the final number of international and local scholars and experts reached 291. The workshop induced various discussions and fruitful results.
Workshop on Advanced Electro-Optical Technology and Education Time: December 23, 2005 (Friday) Place: Room 101, Barry Lam Hall, National Taiwan University Speakers: Dr. Yung S. Liu (Opto-Electronics Systems Laboratories, Industrial Technology Research Institute) Professor Ming C. Wu (Department of Electrical Engineering and Computer Sciences, University of California at Berkeley) Professor Yung-Jui Chen (Department of Computer Science and Electrical Engineering, University of Maryland, Baltimore County) Professor Shin-Tson Wu (College of Optics and Photonics, University of Central Florida) Professor Keh-Yung Cheng (Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign) About the Workshop The Workshop on Advanced Electro-Optical Technology and Education was held on December 23, as a prelude to the biennial Advisory Committee Meeting. Five well-known international and local scholars were invited to give lectures. Dr. Yung S. Liu from the Opto-Electronics Systems Laboratories of the Industrial Technology Research Institute spoke on “Semiconductor Lighting - Technologies and Future Challenges”. With the prospering technological developments in semiconductor light-emitting elements, high effective light-emitting is the foremost advantageous quality. The future trend is to develop semiconductor light-emitting elements into common illuminating/lighting or display apparatuses, including indoor light sources, headlights, and display panels. Currently, the cost of manufacture is an obstacle. It is expected that after lowering the cost, light bulbs and fluorescent lights could be replaced by semiconductor light-emitting elements. The second speaker, Professor Ming C. Wu from UC Berkeley, spoke on the “New Trends in Optical MEMS”. A few years ago when the optical fiber communication market was doing well, researches on optical MEMS focused on optical-communication switches. However, as the market withered, research has taken another direction toward developing CMOS compatible nano-opto-electro-mechanical systems or biophotonics. The fruits of this research area include the micro-disk resonators and optoelectronic tweezers by Professor Wu and his research team. Professor Yung-Jui Chen of University of Maryland spoke on “Future Directions of Planar Lightwave Circuits”. Planar Lightwave Circuits (PLC) is the core technology of photonic integrated photonics and integrated optoelectronics and its application could be extended to photonic communications networks, optical interconnects, and detectors. The key for PLC technology to stride toward large-scale integration are high-contrast refractive-index waveguide materials and adequate platforms. Professor Shin-Tson Wu of University of Central Florida spoke on “Tunable Photonic Liquid Crystal Devices” and stressed the tunable-focus liquid crystal microlenses and their arrays. He and his research team employed special techniques to implement polarization-independent microlenses. Lastly, Professor Keh-Yung Cheng from University of Illinois at Urbana-Champaign spoke on “Hyper-Uniform Nanophotonic Technologies for Ultra-Fast Optoelectronic Systems”. When used in optical communications, the traditional directly-modulated laser diodes, have modulation frequencies up to only 30 GHz; the most critical limiting factor comes from the rates of current injection and electron-hole recombination. The goal of Professor Cheng’s research team is to use high-speed (direct-modulation frequency reaching THz) light-emitting transistor (LET) as the basis for constructing optical interconnect systems faster than 50 GHz.
2005 GIEOE Advisory Committee Meeting Time: December 24, 2005 (Saturday) Place: Room 201, Barry Lam Hall, National Taiwan University Counseling Committee: Dr. Yung S. Liu (Opto-Electronics Systems Laboratories, Industrial Technology Research Institute) Professor Ming C. Wu (Department of Electrical Engineering and Computer Sciences, University of California at Berkeley) Professor Yung-Jui Chen (Department of Computer Science and Electrical Engineering, University of Maryland, Baltimore County) Professor Shin-Tson Wu (College of Optics and Photonics, University of Central Florida) Professor Keh-Yung Cheng (Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign) Vice Administrative Manager Bo-Yan Lu (AUO) About the Meeting During last year’s Christmas Day, cool but nice weather replaced the harsh winds of earlier days. The biennial GIEOE Advisory Committee Meeting was held in Room 201, Barry Lam Hall. Six renowned international and local scholars and experts were invited as advisory committee members to give valuable administrative and research suggestions to our Institute. 21 enthusiastic professors from the Institute attended the meeting, giving presentations on their research, and consulted with the committee members. The entire meeting started from 9 am and lasted until 9 pm. The successful meeting demonstrated the fruits of the Institute’s research in the past two years and brought the year to a wonderful ending. At the opening of the committee member meeting, President Si-Chen Lee and Dean Bing-Huang Chiang of Academic Affairs took time off their busy schedules to address us. Chairman C. C. Yang reported on the current state and gave a summary introduction to the Institute. Besides the research presentations by the individual professors, time was allotted for faculty members and student representatives to interact with the committee members, allowing the professors and students to raise their opinions and all concerns. After the exchange of comments among the committee members, Dr. Yung S. Liu, the Chair of the committee, summarized the suggestions by giving a brief. The meeting consummated a nice conclusion.
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Introducing the Creative Exhibition Center of Image Display Technology
By Professor Jian-Jang Huang, Ms. Hsiao-Ping Chou, and Ms. Li-Chen Tseng With the coming and going of the PC generation, post-PC generation, internet generation, post-internet generation, the 21 century is undoubtedly the era of consumer electronics. As mp3 players, 3G cell phones, and flat-panel displays become the hot items of the 3C market and indispensable image-display interfaces, the creativity of image display and the combination of other consumer electronics gradually become issues that concern everyone. In the middle of 2005, under the direction of Chairman, Prof. C. C. Yang, we began planning for the Creative Exhibition Center of Image Display Technology. This project was subsidized by the “Image Display Technology and Talent Fostering Project” of the Ministry of Education. BenQ, AUO, and Quanta Display Inc. donated 11 32-inch TFT-LCD television sets, which have been installed in the Electrical Engineering Building II, Barry Lam Hall, and Detian Hall to play digital image contents during class time. The displayed contents can be divided into the following categories: 1. department- and college-related activities and student activities; 2. introduction of new technologies; 3. interesting images, pictures, and animations; 4. English lessons; 5. news and weather forecast; 6. health-related issues. We welcome staff and students from the College of Electrical Engineering and Computer Science to provide information on activities and quality programs, and to comment on the aired programs.
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The major facilities of molecular beam laboratory are two VG V-80H molecular beam epitaxy (MBE) systems, a solid source system and a gas source system, which have been devoted on the growth of III-V compound alloys and devices for over a decade. The past research works conducted in this laboratory included AlGaAs/GaAs and InAlAs/InGaAs heterojunction bipolar transistors (HBTs), 980 nm InGaAsP/InGaAs strain-compensated quantum well (QW) lasers, mid-infrared (MIR) InAs/InGaAs strained QW lasers, InAsN diluted nitride QW and lasers, InAs quantum dot (QD) and lasers, and GaAsSb/GaAs type-II QWs . The works on InAs QD and GaAsSb QW devices are still persisting. Our interest is on the feasible growth methods to manipulator the size and density of the QD for extending the emission wavelength of the lasers. For type-II QW, the band line-up engineering by introducing indium or nitrogen into GaAsSb is currently under investigation. The purposes are to understand the band structure of these alloys and to optimize the performances of optoelectronic devices through the adjustment of band gap and band offset. In additions, we also devoted to the research of 3-5 mm Sb-based MIR materials including InAsPSb quaternary and InGaAsPSb quinternary. Our target is to find suitable alloy composition for QW or QD structures for low cost and high efficient MIR light sources.
Nano-meter is equal to 10-9 meter, used to measure the length of a dimension. When semiconductors or material with its size of structures as small as a few nanometers, quantum effects appear. Then their physics and optoelectronic behaviors are different from classical physics. For example, quantum wells have specific quantized energy levels, which can improve the performance of semiconductor lasers, so quantum-well lasers are popularly used in many areas now. In past years, we have put different types of quantum wells in the same device, each type of quantum well corresponding to its own emission wavelength and bandwidth. In this way, the overall bandwidth increases several times, so one single semiconductor optical amplifier is able to cover the entire optical-communication band, almost from 1300 nm to 1600 nm. Recently nano-meter research has attracted even more attractions because lots of behaviors in this scale are beyond what were expected before. In the Si semiconductors, we found that nano-structures/particles could change the recombination behaviors of electrons and holes, increasing the light emission efficiency of Si to beyond previous expectation for indirect-bandgap crystals. However, the influences of nano-meter scale could be positive or negative. In the fabrication of nano-structures or applications of nano-particles, we have to maintain the good quality of Si crystals so that the non-radiative recombination is low. We are highly interested in the photonic applications using nano-structures. We will investigate the influences of nano-structures on optoelectronics, apply nano-structures in optoelectronic components, study new techniques for fabricating nano-structures. Hope to combine the photonics and electronics together on a single Si chip for inter-chip or on-chip optical communication.
(1). CMOS Optoelectronics: The light emitting diodes (LEDs) and photodetectors using available CMOS technology are our focus in the field of optoelectronics. Now the LED efficiency is being improved effectively with nanotechnology enhancements such as Ge/SiC/SiGe quantum dots, surface plasmom, high-k dielectric, nanoroughness and external mechanical strain. The photodetectors are widely used in night-vision scope, video recorder, and digital camera. The germanium on insulator (GOI) phodetectors manufactured by direct wafer bonding and smart cut techniques can increase the responsivity and the speed. Although the charge coupled device (CCD) is the most important photodetector, it has a slow data record speed because the output data should be sequential read out. The first MIS Tunneling LED and MIS Tunneling photodetector are proposed by our group. The MIS structure includes ultra-thin oxide layer (only a few nm) and photocurrent can tunnel though it from metal gate to Si substrate. The MIS Tunneling photodetectors have the benefits of simplicity, fast, low cost, and easily compatible with circuits on Si substrate. (2). Device Simulation and Modeling: Simulation and Modeling on Si/Ge HBTs, strained Si, and Si/Ge HPTs are proposed. The Models of RF and digital circuit are also developed. (3). Strained Si CMOS and Si/Ge HBTs: Due to the scaling of devices, the traditional CMOS process can not satisfy the requirements of ITRS Roadmap. At present, the technique of strained Si has been widely used in the industry. Strained Si devices have a speed enhancement of 10-20% due to the high carrier mobility. The technique of package/mechanical strain is developed to optimize the design and characteristics of devices. (4). Ge FET: There are many papers about Ge proposed because the carrier mobility of Ge is higher than that of Si. However, the Ge-based device can not be available due to the instability of Ge oxide. We use a new structure to manufacture the first Ge FET. It not only has very low defect densities but also improves the hole mobility remarkably due to the mechanical strain. (5). CMOS and Si/Ge HBT Design: We focus on RF circuit design, including the power amplifier (PA) and trans-impedance amplifier (TIA). And we verify that the performance of circuit is improved by the theory of strained Si. The circuits such as ring oscillator and TIA are being optimized to use the strained Si devices. For pure bipolar, the power PA for 802.11a+b+g is being developed by using low cost SiGe HBTs. The integrated photodetectors and TIA are being developed. (6). Rapid Thermal Process (RTP) Equipments: In addition to the well-equipped functions such as RTA, RTO, and RTCVD, a new wafer bonding technique is developed. It not only reduces the cost but also improves the uniformity very well.
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Graduate Institute of Electro-Optical Engineering, National Taiwan University