Summary of Z.L. Wang’ Achievements
Dr. Z.L. Wang received his Ph.D in Physics from Arizona State University in 1987, and he is a now the Hightower Chair in Materials Science and Engineering, Regents' Professor, College of Engineering Distinguished Professor and Director, Center for Nanostructure Characterization, at Georgia Tech. He served as a Visiting Lecturer in SUNY (1987-1988), Stony Brook, as a research fellow at the Cavendish Laboratory in Cambridge (England) (1988-1989), Oak Ridge National Laboratory (1989-1993) and at National Institute of Standards and Technology (1993-1995) before joining Georgia Tech in 1995.
Dr. Zhong Lin (ZL) Wang is the Hightower Chair in Materials Science and Engineering, Regents' Professor, Engineering Distinguished Professor and Director, Center for Nanostructure Characterization, at Georgia Tech.
Dr. Wang has made original and innovative contributions to the synthesis, discovery, characterization and understanding of fundamental physical properties of oxide nanobelts and nanowires, as well as applications of nanowires in energy sciences, electronics, optoelectronics and biological science. He is the leader figure in ZnO nanostructure research. His discovery and breakthroughs in developing nanogenerators establish the principle and technological road map for harvesting mechanical energy from environment and biological systems for powering a personal electronics. His research on self-powered nanosystems has inspired the worldwide effort in academia and industry for studying energy for micro-nano-systems, which is now a distinct disciplinary in energy research and future sensor networks. He coined and pioneered the field of piezotronics and piezo-phototronics by introducing piezoelectric potential gated charge transport process in fabricating new electronic and optoelectronic devices. This historical breakthrough by redesign CMOS transistor has important applications in smart MEMS/NEMS, nanorobotics, human-electronics interface and sensors. Wang also invented and pioneered the in-situ technique for measuring the mechanical and electrical properties of a single nanotube/nanowire inside a transmission electron microscope (TEM).
Dr. Wang is a pioneer and world leader in nanoscience and nanotechnology for his outstanding creativity and productivity. He has authored and co-authored 5 scientific reference and textbooks and over 700 peer reviewed journal articles (14 in Nature and Science, 6 in Nature sister journals), 45 review papers and book chapters, edited and co-edited 14 volumes of books on nanotechnology, and held 32 patents. Dr. Wang is the world’s top 5 most cited authors in nanotechnology. His entire publications have been cited for over 45,000 times. The H-index of his publications is 104. He has delivered over 700 keynote, plenary and invited talks at international and national conferences as well as universities and research institutes worldwide.
Dr. Wang was elected as a foreign member of the Chinese Academy of Sciences in 2009, member of European Academy of Sciences in 2002, fellow of American Physical Society in 2005, fellow of AAAS in 2006, fellow of Materials Research Society in 2008, fellow of Microscopy Society of America in 2010, and fellow of the World Innovation Foundation in 2002. He is an honorable professor of over 10 universities in China and Europe. He received 2011 MRS Medal from the Materials Research Society, 1999 Burton Medal from Microscopy Society of America, 2001 S.T. Li prize for Outstanding Contribution in Nanoscience and Nanotechnology, the 2009 Purdy Award from American Ceramic Society, NanoTech Briefs, Top50 award in 2005, the 2000 and 2005 Georgia Tech Outstanding Faculty Research Author Awards, Sigma Xi 2005 sustain research awards, Sigma Xi 1998 and 2002 best paper awards, NSF CAREER in 1998. His breakthrough researches in the last 15 years have been featured by over 50 media world wide including CNN, BBC, FOX News, New York Times, Washington Post, NPR radio, Time Magazine, National Geography Magazine, Discovery Magazine, New Scientists, and Scientific America. Dr. Wang is the list of the world’s greatest scientists (http://superstarsofscience.com/scientists ).
Wang invented the nanogenerators and first established their working mechanism for harvesting mechanical energy using nano-enabled technology (Science, 312, (2006) 242; >830 citation). Developing novel technologies for wireless nanodevices and nanosystems are of critical importance for in-situ, real-time and implantable biosensors. An implanted wireless biosensor requires a power source, which may be provided directly or indirectly by charging of a battery. It is highly desired for wireless devices and even required for implanted biomedical devices to be self-powered without using battery. Therefore, it is essential to explore innovative nanotechnologies for converting mechanical energy, vibration energy, and hydraulic energy into electric energy that will be used to power nanodevices without using battery. A groundbreaking research by Wang in 2006 is the invention of the piezo-electric generators for self-powered nanodevices. He demonstrated an innovative approach for converting nano-scale mechanical energy into electric energy by piezoelectric zinc oxide nanowire arrays. By deflecting the aligned nanowires using a conductive atomic force microscopy (AFM) tip in contact mode, the energy that was first created by the deflection force and later converted into electricity by piezoelectric effect has been measured for demonstrating nano-scale power generator. The operation mechanism of the electric generator relies on the unique coupling of piezoelectric and semiconducting dual properties of ZnO as well as the delicate rectifying function of the Schottky barrier formed between the metal tip and the nanowire. This research was chosen as the world top 10 most outstanding discovery in science by the Chinese Academy of Sciences. Wang was featured by Science Watch in Dec. 2008 issue for his pioneer work in nanogenerator.
Wang has demonstrated his outstanding creativity through the development of science, engineering and technological road map by applying nanogenerators to drive personal electronics. Wang has developed the first microfiber-nanowire hybrid nanogenerator (Science 316 (2007) 102, citation 380; Nature 451 (2008) 809-813, >210 citation; Nature Nanotechnology 4 (2009) 34), establishing the basis of using textile fibers for harvesting mechanical energy. The principle and technology demonstrated have the potential of converting mechanical movement energy (such as body movement, muscle contractions, blood pressure), vibration energy (such as acoustic/ultrasonic wave), and hydraulic energy (such as flow of body fluid, blood flow, contraction of blood vessel) into electric energy that may be sufficient for self-powering nanodevices and nanosystems. Recently, Wang has made ground-breaking progress in scale up the output of the nanogenerators through three-dimensional integration, so that the output voltage reached 3-10 V and the continuous output power reaches 10-100 uW (accumulative output power is 50 mW), which has been applied nanogenerator to drive a commercial LED and LCD (Nano Letters, 10 (2010) 5025; Nano Letters, 10 (2010) 3151), clearly demonstrating its outstanding potential for powering sensors and personal electronics. The prototype technology established by the nanogenerator sets a platform for developing self-powering nanosystems with important applications in implantable in-vivo biosensors, wireless and remote sensors, nanorobotics, MEMS and sonic wave detection (Scientific American, January issue (2008) 82). The nanogenerator is selected by New Scientist as the top 10 most potential technologies in the coming 30 years, which will be as important as the invention of cell phone, and is among the top 20 featured nanotechnologies by Discovery Magazine in 2010. The fiber based nanogenerator was selected as the top 10 most important emerging technologies in 2008 by the British Physics World, MIT Technology Review, and Beijing Daily newspaper.
Wang coined and pioneered the field of piezotronics, which couples piezoelectric and semiconducting properties of nanowires and nanobelts for designing and fabricating of electronic devices and components, such as piezoelectric field effect transistors and piezoelectric diodes. Owing to the polarization of ions in a crystal that has non-central symmetry, a piezoelectric potential (piezopotential) is created in the material by applying a stress. This internal field created inside of a ZnO nanowire can effectively tune the Schottky barrier height between the nanowire and its metal contact, which can effectively tune and gate the charge carrier transport process across the interface. This is the piezotronic effect first proposed by Wang in 2007 (Advanced Materials, 19 (2007) 889), based on which piezoelectric field effect transistor, piezoelectric diode and strain gated logic operations have been developed by Wang. The electronics fabricated by using the piezopotential as a gate voltage is coined piezotronics. The design of piezotronics fundamentally changes the design of traditional CMOS transistor in three ways: the gate electrode is eliminated so that the piezotronic transistor only has two leads; the externally applied gate voltage is replaced by an internally created piezopotential so that the device is controlled by the strain applied to the semiconductor nanowire rather than gate voltage; the transport of the charges is controlled by the contact at the drain (source)-nanowire interface rather than the channel width. Piezotronics has applications in human-computer interfacing, smart MEMS, nanorobotics and sensors. Piezotronics was chosen as the top 10 emerging technology in 2009 by the MIT Technology Review.
Due to the polarization of ions in a crystal that has non-central symmetry, a piezoelectric potential (piezopotential) is created in the crystal under stress. Piezopotential can effectively raise the Schottky barrier height at a metal-semiconductor interface or change the transtransport at a p-n junction, while laser excitation and effectively low the Schottky barrier height. Therefore, we can use the coupling between piezoelectric effect and laser excitation to introduce new optoelectronic devices. Piezo-phototronics effect is a result of three-way coupling among piezoelectricity, photonic excitation and semiconductor transport, which allows tuning and controlling of electro-optical processes by strain induced piezopotential. The piezo-phototronic effect was first coined by Wang in 2009. Recently, we have applied this effect for fabricating high sensitive UV sensors, largely enhancing LED efficiency, high performance solar cells. The development of piezo-phototronics will have great impact to the energy science and optoelectronic devices fabricated using ZnO and GaN materials.
Wang is widely credited for the discovery and synthesis of oxide nanobelts (Science, 209 (2001) 1947; > 3200 citation). The nanobelts are a new class of one-dimensional nanostructures denoting a wide range of semiconducting oxides with cations of different valence states and materials of distinct crystallographic structures. Wang's pioneering work opened a new chapter in functional nanomaterials for building nanodevices. This landmark paper is among the list of the top 30 most influential papers published in Science in the last 10 years, the top 10 most cited paper in materials science in last decade. The rational approach outlined in this work has subsequently served to nucleate a large body of studies by other researchers worldwide. As a result, ZnO is the most exciting type of one-dimensional nanostructures for oxides that holds equal importance to Si nanowires and carbon nanotubes. Wang has been the world leader in studying of ZnO nanostructures.
Wang was the first who synthesized and understood the growth processes of novel oxide nanostructures.Owing to the positive and negative ionic charges on the zinc- and oxygen-terminated ZnO basal planes, respectively, a spontaneous polarization normal to the nanobelt surface is induced. As a result, helical nanosprings/nanocoils are formed by rolling up single crystalline nanobelts and nanorings (Science, 303 (2004) 1348; > 700 citation; Science, 309 (2005) 1700; >370 citation). These are the first papers that described the spontaneous polarization-induced novel nanostructures and they open a new direction of research for studying piezoelectric properties at nano-scale.
Wang pioneered the field of in-situ nanomeasurements in transmission electron microscopy on the mechanical, electrical and field emission properties of individual nanotubes, nanobelts and nanowires.Characterizing the physical properties of carbon nanotubes is limited not only by the purity of the specimen but also by the size distribution of the nanotubes. Traditional measurements rely on scanning probe microscopy. Based on transmission electron microscopy, Wang and his colleagues have developed a series of unique techniques for measuring the mechanical, electrical and field emission properties of individual nanotubes in 1999. His in-situ TEM technique is not only an imaging tool that allows a direct observation of the crystal and surface structures of the material at atomic-resolution, but also an in-situ apparatus that can be effectively used to carry out nano-scale property measurements (Science, 283 (1999) 1513; >940 citation). A nanobalance technique and a novel approach toward nanomechanics have been demonstrated (Phys. Rev. Letts. 85 (2000) 622), which was selected by APS as the breakthrough in nanotechnology in 1999. This study creates a new field of in-situ nanomeasurements in materials science and mechanics.
Wang is an extremely influential scientist in materials science and fundamental electron microscopy. His textbook entitled of Functional and Smart Materials - structural evolution and structure analysis (Plenum Press, 1998) is "a unique, cutting-edge text on smart materials ... it is recommended as an adjunct to device design books used for engineers as well as scientists during the development of smart devices and structures" (Physics Today , Nov. 1998, p. 70). His textbook on Elastic and Inelastic Scattering in Electron Diffraction and Imaging (Plenum Press, 1995) is "a noteworthy achievement and a valuable contribution to the literature" (American Scientist, 1996). His textbook onReflected Electron Microscopy And Spectroscopy For Surface Analysis (Cambridge University Press, 1996) is “a book that any materials science or physics library should be holding" (MRS Bulletin, Oct., 1998).
B.S. Northwest Telecommunication Engineering Institute (currently Xidian University), China, 1982
Ph.D. Arizona State University, 1987