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SRC Proposal Principle Investigator
SRC Proposal Reference_Spintronics
SRC Proposal Reference_ZnO on Si Technology

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Resume

(i)        Dr. Lu is a professor in the Department of Electrical and Computer Engineering, and a Graduate Faculty member in both Electrical and Computer Engineering and Materials Science programs at Rutgers. His major research field is microelectronic materials and devices. At Rutgers, Dr. Lu did research on the basic recombination mechanisms in C-doped GaAs, which led to the optimum design and demonstration of high performance HBTs. His group and industrial collaborators demonstrated highly compact optical waveguides and high efficiency optical bends using Ge on GaAs, which can significantly increase the density of components in an optical integrated chip. He invented a unique bonding technology to generate controllable in-plane anisotropic strain in thin layers of semiconductor multiple quantum wells for exceedingly high contrast light modulators. MEMS technology was applied to fabricate a novel vacuum microdiode which is composed of a Si ultra-shallow junction as an avalanche cathode and an on-chip cantilever beam as an anode, used for advanced flat-panel displays. Dr. Lu has worked for a long time in the area of oxide thin films and their devices, including ZrO, RuO, CeO, LBO, and BST, etc. Recently Professor Lu’s group has grown high quality epitaxial ZnO and Mg_xZn_1-xO films and ZnO nanotips on various substrates by MOCVD. His group has invented an MOCVD selective growth technique to integrate ZnO nanotips and epitaxial films on the same SOS substrate. ZnO based multilayer structures have been used to demonstrate various new devices, including the first Schottky diode on epitaxial ZnO films, the first optically addressed high contrast (70:1) and high speed (~100ps) UV light modulator which exploits the in-plane anisotropy in epitaxial ZnO films grown on R- sapphire; the first high speed ZnO thin film based MSM photoconductive and photovoltaic (Schottky) UV photodetectors; and high frequency low loss SAW filters and integrated BAW resonators, ZnO UV-SAW detectors, and nano-SAW biosensors. The results have been presented at the World’s Best Technology Fair (http://www.wbt02.com). In collaboration with industries, Dr. Lu’s group has also conducted research on high frequency passive components for telecommunication, including the high Q-value integrated RF inductors on Si MCM chips, and Si monolithic RF spiral transmission line baluns operating at 1.2 – 3.5 GHz. He has over 160 refereed articles, 200 conference presentations and invited talks, and 14 U.S. patents. 14 Ph.D. and 12 M.S. students of Electrical Engineering and Materials Science have received their degrees under his direction. His students have received awards, including Rhodes Scholar, NSF Graduate Fellowship, National Research Council Fellowship, USA-TODAY All-USA College First Academic Team, and HP and Lockheed Martin Undergraduate Research Fellowships. Three graduate students received four Outstanding Student Paper awards in international conferences. Dr. Lu received the 1993 Warren I. Susman Award for Excellence in Teaching, the highest teaching award at Rutgers. In 1994 he received the Rutgers University Board of Trustees Research Fellowship award for Scholarly Excellence, and the IEEE Outstanding Student Counselor and Advisor Award in 1995. In 2002, Prof. Lu was one of the two recipients of the Rutgers Teacher-Scholar award. In 2004, he was promoted to Professor II (Distinguished) at Rutgers.

(ii)      Co-organized the 2^nd International ZnO Workshop (Dayton, 2002); Organization Committee of the 3^rd and 4^th International ZnO Workshops (Sendai, 2004 and Giessen, 2006); Session Chairman of AFOSR ZnO conference (Hawaii, 2004); Organization Committee and Co-chairman in ZnO session of 2005 and 2006 Electronic Material Conference (2005 EMC at UCSB, 2006 EMC at Penn. State). He is the Associate Director for Research at the NJ Commission of Science Technology Excellence Center of Multifunctional Sensors (MUSE) (2003)

(iii)     Reviewer for NRC, NSF, DOD and 14 journals.
 

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ACADEMIC DEGREES
B.S. Applied Physics, Jiao Tong University, Shanghai, China 1982
Ph.D. Electrical Engineering, University of Colorado, Boulder, USA 1988

EMPLOYMENT HISTORY

• 2004 - present: Professor II, Department of Electrical and Computer Engineering

• 2000 - 2004:     Professor I, Department of Electrical and Computer Engineering

• 1994 - 2000:     Associate Professor, Department of Electrical and Computer Engineering

• 1988 ‑ 1994:     Assistant Professor, Department of Electrical and Computer Engineering

• 1992 ‑ present: Member, Faculty of Materials Science, Graduate School

HONORS AND AWARDS

• 2002: Rutgers Scholar- Teacher Award, Rutgers University

• 2001-present: Guest Professor, Shanghai Jiao Tong University

• 2001-present: Guest Professor, Shangdong University

• 1989-2002: Faculty Academic Service Award, Rutgers University

• 1995: IEEE Oustanding Student Counselor and Advisor Award, IEEE

• 1994: Board of Trustee’s Research Fellowship Award for Scholarly Excellence, Rutgers University

• 1993: Warren I. Susman Award for Excellence in Teaching, Rutgers University

• 1991: National Science Foundation Initiation Award

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RECENT PROGRESS

Most of work has focused on the MOCVD growth of high quality epitaxial ZnO and MgxZn1-xO layers, nanostructures, and device applications. The most works are based on foundation established under three NSF grants: (i) ECS-0224166, "Development of ZnO Based Room Temperature Spintronics"; (ii) ECS-0088549, "Monolithically Integrated Tunable ZnO SAW Chip"; and (iii) CCR-0103096 "Feasibility Studies on ZnO Nanostructures and Their Device Applications". Our ZnO research so far has resulted in more than 25 refereed journal publications, 70 conference proceedings and presentations, and 8 patent awards.

1. ZnO Material Growth

We have grown high quality epitaxial ZnO thin films on r-plane sapphire (r-Al₂O₃) by metal organic chemical vapor deposition (MOCVD) at low temperature (350°C - 500°C). The epitaxial relationship between ZnO films and r-Al₂O₃ substrates was identified using X-ray diffraction. The FWHM of the band edge emission photoluminescence (PL) peak measured at 11°K is 6 meV. The interface is atomically sharp and semicoherent, as evaluated by high resolution TEM.

The effects of annealing on the ZnO/r-Al₂O₃ structure and its thermal stability have been studied in detail. Recently, high quality epitaxial wurtzite Mg_xZn_1-xO (0 £x £0.33) films on r-Al₂O₃ substrates have been developed. We have achieved transparent conductive ZnO through in-situ Ga doping during MOCVD growth. Piezoelectric wurtzite Mg_xZn_1-xO (0<x<0.33) epitaxial films on r-plane sapphire have been developed for SAW and BAW devices, with Li doping to compensate excess carriers. This work serves as a strong technological base for the ZnO/GaN tunable SAW device work in this proposal. Under the NSF grant ECS-0224166, we have conducted studies on TM doped ZnO epitaxial films for room-temperature spintronics. Mn-doped ZnO films show a well-defined transition in the magnetization near 45K that is consistent with a transition from a ferromagnetic to paramagnetic state.  Our current progress provides the way to ex-situ dope ZnO through implantation. More significantly, our breakthrough in in-situ doping of ZnO through MOCVD promises development of multifunctional ZnO multiplayer structure for room temperature spintronics. High quality epitaxial Fe-doped ZnO films on r-sapphire are grown by MOCVD for the first time. Room temperature ferromagnetism is confirmed by SQUID measurements in the films, as shown in fig. 1(b). Our achievements of nanostructured ferromagnetic ZnO successfully integrate nanotechnology and spintronics into ZnO which will have great potential applications. Room temperature ferromagnetism is also observed in Fe-doped ZnO nanostructures. The Fe-doped ZnO nanostructures show better magnetic response compared to their film counterparts. Our group has achieved conductivity tailoring in Ga doped ZnO epitaxial films and nanotips, with an electron concentration of > 10²⁰ cm^-3 and an optical transmission > 85% at 400nm.

 

       2. ZnO Based Devices

We have demonstrated the first high speed ZnO MSM UV photodetector, using epitaxial ZnO on r-Al₂O₃. The devices show high photoresponsitivity (400A/W at 5V bias). The response speed (~1ms) is much faster than published results (tens ms to hundreds of ms) due to the high material quality. We have demonstrated the first ZnO Schottky diode, as well as the first ZnO Schottky photodetector which has a fast photoresponse component with rise and fall times of tens of nanoseconds, and a leakage current of ~1 nA at 5 V bias. In collaboration with the US Army Research Labs, we have reported the first optically addressed normal incidence high contrast UV modulator that exploits the in-plane optical anisotropy in epitaxial ZnO on r-Al₂O₃. An ultra-fast dynamic polarization rotation of ~12° and a high contrast ratio of 70:1 were achieved. ZnO thin film based SAW devices with piezoelectric coupling coefficients up to 6% in the ZnO/r-Al₂O₃ material system have been demonstrated. The piezoelectric behavior of Mg_xZn_1-xO was shown for the first time in SAW and BAW  devices. We have also employed the ZnO/SiO₂/Si system for temperature compensated SAW filters integrated with ICs. Our group has developed both alloyed and non-alloyed ohmic contacts to ZnO with low contact resistance. Under NSF ECS-0088549, we developed a novel electrically or optically tuned monolithically integrated tunable SAW (MITSAW) chip technology on the ZnO/r-Al₂O₃ system. An optically tuned SAW device was demonstrated for zero-power remote wireless sensing applications.
 

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PATENTS

• "Zinc Oxide Nanotip and Fabricating Method Thereof", (with S. Muthukumar*, N.W. Emanetoglu*), U.S. Patent No. 6,979,489. (Dec. 27, 2005)

• "Schottky Diodes with Silver Layer Contacting the ZnO Mg_xZn_1-xO films", (with H. Sheng*, S. Muthukumar*, N.W. Emanetoglu* and J. Zhong*), U.S. Patent No. 6,846,731. (July 7, 2005)

• "Multifunctional Biosensor Based on ZnO-based Nanostructures" (with Z. Zhang*, H. Sheng*, N.W. Emanetoglu*, M. Inouye, O. Mirochnitchenko), U.S. Patent No. 6,914,279 (July 5, 2005)

• "Integrated tunable surface acoustic wave technology and sensors provided thereby", (with  N.W. Emanetoglu*), US Patent No 6,621,192 (Sept. 16, 2004)

• "Tailoring Piezoelectric Properties Using Mg_xZn_1-xO/ZnO Material and Mg_xZn_1-xO/ZnO Structures", (with N.W. Emanetoglu*), US Patent No 6,716,479, (April 6, 2004)

• "Integrated tunable surface acoustic wave technology and sensors provided thereby", (with N.W. Emanetoglu*), US Patent No 6,710,515 (Mar. 23, 2004)

• “Integrated Tunable Surface Acoustic Wave with Quantum Well Structure Technology and Systems Provided Thereby” (with N.W. Emanetoglu*), U.S. Patent No. 6,559,736. (May 6, 2003).

• “Programmable SAW Filter”, (with J.Zhu*, J. Kosinski, and R. Pastore), U. S. Patent No. 6, 541, 893. (Apr. 1. 2003)

• “High Contrast, Ultrafast Optically Addressed Ultraviolet Light Modulator Based Upon Optical Anisotropy in ZnO Films Grown on R-plane Sapphire” (with M. Wraback, H. Shen, S. Liang* and C.R. Gorla*), US Patent No.6,366,389 (April 2, 2002)

• "Dynamic Modulation of Quantum Devices," (with A. Ballato, R.H. Wittstruck*, M. Dutta, J. Pamulapati and H. Shen), US. Patent No. 5,847,435. (December 1998)

• "Piezoelectric Resonator," (with J. Kosinski*), U.S. Patent No. 5,422,533.  (June 1995)

• "Uniaxially Strained Semiconductor Multiple Quantum Well Spatial Light Modulator Using Direction‑Dependent Thermal Expansion Coefficients in a Host Substrate," (with A. Ballato, J. Kosinski*, H. Shen, and M. Dutta), U.S. Patent No. 5,381,260. (May 1995)

• "Crystal Resonator with Multiply Segmented Lateral‑field Excitation Electrodes," (with J.A. Kosinski*, and A. Ballato), U.S. Patent No. 5,414,322. (January 1995).

* denotes the students supervised by Dr. Lu.

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