Dr. Zhi Chen's Group
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Dr. Zhi David Chen


Department of Electrical & Computer Engineering College of Engineering
University of Kentucky
453 Anderson Hall 
Lexington, KY 40506-0046 
Phone:(859) -218-6550
Fax : (859) - 257 - 3092
email : zhichen@engr.uky.edu

Electronic Devices and Materials 

Exploring Future Photovoltaic Devices

Welcome to visit my group home page! It is a rewarding career in my research group. My current research focuses on studies of low-cost and high efficiency photovoltaic  devices utilizing novel nanoscale materials. One of the examples is the emerging perovskite materials. Our group has long experience in fabrication and characterization of semiconductor devices and sensors using novel nanoscale materials. The graduates in my research area are highly demanded in industry (See Group Member Page). I always need outstanding people! Please feel free to send me your resume. 

Dr. Chen's Research Accomplishment

Google Scholar Citation: http://scholar.google.com/citations?user=lW-EfMYAAAAJ&hl=en&oi=ao

TiO2 Nanotubes and Carbon Nanotubes. Dr. Chen had extensive experience in anodization of aluminum when he worked on humidity sensors in 1989-1992. In 2001, working with Dr. Dawei Gong, his postdoctoral research associate, and Prof. Craig A. Grimes who was then at Kentucky, he successfully created TiO2 nanotubes through anodization of pure titanium, a new type of inorganic oxide nanotubes. This idea came from his past experience in humidity sensor research using anodization. As the corresponding author, Prof. Chen first presented this work at Symposium Z3.9, 2001 MRS Fall Meeting, Nov. 26-29, 2001, Boston, MA, USA (http://www.mrs.org/f01-program-z/). The first author, Dr. Dawei Gong, moved with Prof. Craig A. Grimes to Penn State University, where the work was submitted to J. Mater. Res. with a wrong address of Prof. Chen, Wenchong Hu, and Suresh Singh. The paper entitled Titanium Oxide Nanotube Arrays Prepared By Anodic Oxidation” was published in J. Mater. Research 16, 3331-3334, 2001, Citation: >1,800 on Google Scholar. In addition, he and his co-workers fabricated the first vertically aligned carbon nanotube (CNT) arrays with high density and uniformity on silicon substrates using porous anodic aluminum oxide (AAO) as templates (“Growth of well-aligned carbon nanotube arrays on silicon substrate using porous alumina film as nanotemplate”, Appl. Phys. Lett. vol. 79, 3083-3085, 2001, Citation: >140 on Google Scholar; “Ethylene flame Synthesis of well-aligned multi-walled carbon nanotubes”, Chem. Phys. Lett. vol. 346, pp. 23-28, 2001, Citation: >150 on Google Scholar ). This provides a possibility for integration of carbon nanotube arrays with silicon electronics. The above research has a large impact on nanoscale material research community.
Drift-free moisture sensor. Working with his colleagues
at University of Electronic Science & Technology, Chengdu, China, Dr. Chen developed the world’s first reliable and drift-free humidity/moisture sensor for trace moisture measurement (<1 ppmv) using anodization (J. Am. Ceram. Soc., vol. 74, pp. 1325-1330, 1991, and Proc. 27th annual conference, IEEE  Industry Application Soc., Houston, TX, Oct. 1992, vol. 2, pp1668-1675). He won two awards for this contribution: The Second Prize Paper Award, Industrial Automation and Control Committee, the 27th Annual Conference, IEEE Industry Application Society, USA, 1992 and The National Award for Invention: The Third Prize Award, Ministry of Science & Technology, China, 1995. His recent technical review about this drift-free moisture sensor and other humidity sensors has made a large impact on humidity sensor research (“Humidity sensors: a review of materials and mechanisms”, Sensor Letters vol. 3, 274-295, 2005,Citation: >490 on Google Scholar). After further research and development (with two US patents and one Chinese patent filed), this novel sensor is being commercialized in Advanced Semiconductor Processing Technology  LLC (ASPT USA), Lexington, Kentucky, USA, and Advanced Semiconductor Processing Technology Chengdu Ltd.  (ASPT Chengdu), Chengdu, Sichuan, China.
Hydgogen/Deuterium (H/D) Isotope Effect. This effect was discovered in 1996 by Drs. Lyding and Hess at University of Illinois at Urbana-Champaign (UIUC). As a graduate student at UIUC, Dr. Chen helped develop this effect into a manufacturing process, so that integrated circuits (microchips) lifetime is dramatically improved (IEEE Electron. Dev. Lett., vol. 19, pp. 444-446, 1998IEEE Electron. Dev. Lett., vol. 21, no. 5, 221-223, 2000). In addition, the classical theory suggested that the hot-electron degradation of MOS transistors was caused by hot electron injection into the gate insulator (SiO2). Based on his  experiments using H/D isotope effect, Dr. Chen proved that it is not the hot-electron injection into the oxide but the hot-electron bombarding the SiO2/Si interface that causes the degradation, (On  the mechanism for interface trap generation in MOS transistors due to channel hot carrier stressing”, IEEE Electron. Dev. Lett., vol. 21, no. 1, 24-26, 2000). This laid a foundation for establishing a more accurate theoretical lifetime model for microchips, which is very important for the reliability of computers, cell phones, and iPods/iPads etc.