Group Members

 • Group Leader

 • PostDocs & Staff

    – Yolande Berta
    – Yong Ding
    – Xudong Wang
    – Liqiang Mai
    – Yong Qin
    – Chengyan Xu

 • Graduate Students

    – Brent Buchine
    – Rusen Yang
    – Jenny Morber
    – Changshi Lao
    – Jin Liu
    – Jinhui Song
    – Wenjie Mai
    – Ben Weintraub
    – Melanie Kirkham
    – Yifan Gao
    – Sheng Xu
    – Qin Kuang

 • Prior Members

  by
Web Nano Site

Summary

in English (.pdf)       in Chinese (.pdf)

    Dr. Z.L. Wang received his Ph.D in Physics from Arizona State University in 1987, and he is a now a Regents?Professor, COE Distinguished Professor and Director, Center for Nanostructure Characterization (CNC), 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).

    Dr. Wang has authored and co-authored four scientific references and textbooks, published over 530 peer reviewed journal articles, 55 review papers and book chapters, edited and co-edited 14 volumes of books on nanotechnology, and held 20 patents and provisional patents. Dr. Wang is the world’s top 25 most cited authors in nanotechnology from 1992-2002 (ISI, Science Watch). His entire publications have been cited for over 21,000 times. The H-index of his publications is 69. He is a fellow of American Physical Society and fellow of AAAS, and he has received the 2001 S.T. Li prize for Outstanding Contribution in Nanoscience and Nanotechnology, the 2000 and 2005 Georgia Tech Outstanding Faculty Research Author Awards, Sigma Xi 2005 sustain research awards, and the 1999 Burton Medal from Microscopy Society of America. He is a member of the editorial boards of over 10 major journals. He is an honorable and guest professor of over 10 universities. Two symposiums (May 7, 2003; Oct. 12, 2005) organized by the University of Pierre & Marie Curie (Paris) and sponsored by the L'Institut Universitaire de France (IUF) in the honor of Prof. Wang for his outstanding contribution in nanotechnology.

Z.L. Wang's full CV (.pdf)

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Leadership

    Under Dr. Wang's leadership and extremely hard work, the Georgia Tech Electron Microscopy Center was established in 1999. This Center not only links numerous research programs and groups on campus, but also is becoming a center for education and collaboration. This Center has been extensively developed and expanded to include 15 major research equipment, and it is now becomes a Center for Nanostructure Characterization and Fabrication (CNCF).

    Dr. Wang is the founding Director for the Center on Nanoscience and Nanotechnology at Georgia Tech, which is playing the most crucial role in organizing GT and other universities for national competition on nanotechnology initiatives launched by federal government. Dr. Wang is also very active in initiating and driving the join research, education and degree programs between Georgia Tech and Peking University (China). He is the Chair of the Department of Advanced Materials and Nanotechnology at Peking University.

    Dr. Wang’s current research focuses on discovery, controlled synthesis, characterization, fundamental understanding and applications of one-dimensional nanostructures in microsystems and biomedical science. His recent research is on semiconducting and piezoelectric oxide nanobelts for electromechanical-coupled nano-scale devices and self-assembly technology.

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Research Grants and Funding

     Dr. Wang is PI or co-PI on numerous proposals. He has received funding from NSF, DOE, DARPA, NASA, NIH China NSF and industry. The total value of contracts awarded in which he has either been PI, co-PI or an investigator is $18M over the past 13 years at Georgia Tech.

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Community Service

     Dr. Wang is actively participating in the activities and services in scientific professional societies. He has served as chair and co-chair for 14 local, national and international conferences organized 10 symposia and chaired over 15 sessions in national and international conferences. He has served as a member for the review panel for NSF, NASA and DOE and advisory board for numerous centers on nanotechnology. He is a referee for numerous prestigious journals, such as Nature, Science, Physical Review Letters, Nature Materials and J. American Chemical Soc.

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On-Going Research

1. Invented nanowire piezo-electric generators for self-powered nanodevices (Science, 312, (2006) 242; Science 316 (2007) 102-104; Nature 451 (2008) 809-813)

     Developing novel technologies for wireless nanodevices and nanosystems are of critical importance for in-situ, real-time and implantable biosensing, biomedical monitoring and biodetection. 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 Dr. 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 (NW) arrays. By deflecting the aligned NWs 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 elegant rectifying function of the Schottky barrier formed between the metal tip and the NW. The efficiency of the NW based piezo-electric power generator is ~ 17-30%.

     Wang has also invented the first DC nanogenerators driven by ultrasonic wave (Science 316 (2007) 102-104). The nanogenerator is composed of aligned ZnO NWs and a zigzag top electrode, which is a novel, adaptable, mobile and cost-effective approach with a great potential in nanotechnology. The NWs can be grown on solid substrates or polymer substrates as flexible power generators. In 2008, he has developed microfiber-nanowire hybrid nanogenerator (Nature 451 (2008) 809-813), establishing the basis of using textile fibers for harvesting mechanical energy. The principle and technology demonstrated here have the potential of converting mechanical movement energy (such as body movement, muscle stretching, 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. The prototype technology established by the DC nanogenerator set a platform for developing self-powering nanosystems with important applications in implantable in-vivo biosensing, wireless and remote sensing, nanorobotics, MEMS, sonic wave detection and more.

2. Nano-Piezotronics [Adv. Mater., 19 (2007) 889]

    Dr. Wang first created a field called nano-piezotronics in Dec. 2006, which utilizes the coupled piezoelectric and semiconducting properties of nanowires and nanobelts for designing and fabricating electronic devices and components, such as field effect transistors and diodes. The physics of nano-piezotronics is based on the principle of nanowire nanogenerator that converts mechanical energy into electric energy. It is anticipated to have a wide range of applications in electromechanical coupled electronics, sensing, havesting/recycling energy from the environment, and self-powered nanosystems.

3. Polar surface induced novel growth processes and mechanism of oxide nanostructures and electromechanical coupled devices (Science 303 (2004) 1348; Science, 309 (2005) 170)

    The wurtzite structure family has a few important members, such as ZnO, GaN, AlN, ZnS and CdSe, which are important materials for applications in optoelectronics, lasing and piezoelectricity. The two important characteristics of the wurtzite structure are the non-central symmetry and the polar surfaces. The structure of ZnO, for example, can be described as a number of alternating planes composed of tetrahedrally coordinated O2- and Zn2+ ions, stacked alternatively along the c-axis. The oppositely charged ions produce positively charged (0001)-Zn and negatively charged (000-1)-O polar surfaces, resulting in a normal dipole moment and spontaneous polarization along the c-axis. This polar surface gives rise a few interesting growth features.

    The breakthroughs by Wang’s group in 2004 is the success of first piezoelectric nanobelts and nanorings (Science 303 (2004) 1348) for applications as sensors, transducers and actuators in micro- and nano-electromechanical systems. 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. The mechanism for the helical growth is suggested for the first time to be a consequence of minimizing the total energy contributed by spontaneous polarization and elasticity. The nanobelts have widths of 10-60 nanometers and thickness of 5-20 nanometers, and they are free of dislocations. The polar surface dominated ZnO nanobelts and helical nanosprings are likely to be an ideal system for understanding piezoelectricity and polarization induced ferroelectricity at nano-scale.

    The major discovery made by Wang’s group in 2005 was the discovery of a new rigid helical structure of zinc oxide consisting of a superlattice-structured nanobelt (Science, 309 (2005) 170), which was formed spontaneously in a vapor-solid growth process. Starting from a single-crystal stiff-nanoribbon dominated by the c-plane polar-surfaces, an abrupt structural transformation into the superlattice-structured nanobelt led to the formation of a uniform nanohelix due to a rigid lattice rotation or twisting. The nanohelix was made of two types of alternating and periodically distributed long crystal stripes, which were oriented with their c-axes perpendicular to each other. The nanohelix terminated by transforming into a single-crystal nanobelt dominated by nonpolar surfaces. The nanohelix could be manipulated, and its elastic properties were measured, which suggests possible uses in electromechanically-coupled sensors, transducers and resonators.

4. Nanobelts of semiconducting oxides: from materials, to properties and to devices (Science, 209 (2001) 1947)

    Recently a series of binary semiconducting oxide nanobelts (or nanoribbons), such as ZnO, In2O3, Ga2O3, CdO and PbO2 and SnO2 have been successfully synthesized in Dr. Wang’s laboratory by simply evaporating the source compound (Science, 209 (2001) 1947). The as-synthesized oxide nanobelts are pure, structurally uniform, single crystalline and most of them free from defects and dislocations; they have a rectangular-like cross-section with typical widths of 30?-300 nm, width-to-thickness ratios of 5?-10 and lengths of up to a few millimeters. The belt-like morphology appears to be a unique and common structural characteristic for the family of semiconducting oxides with cations of different valence states and materials of distinct crystallographic structures. The nanobelts are an ideal system for fully understanding dimensionally confined transport phenomena in functional oxides and building functional devices along individual nanobelts. This discovery has been reported by over 20 media and professional society journals. The paper (Science, 209 (2001) 1947) has been the the second most cited paper in chemistry according to Science Watch (ISI). Dr. Wang’s group has recently applied the nanobelt materials to make the world’s first field effect transistor, single wire sensors and nano-size cantilevers for scanning probe microscopy. This invention has been highlighted by Nature as research news (Nature 423 (2003) 134).

5. In-situ nanomeasurements on the mechanical, electrical and field emission properties of nanotubes, nanoblets 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, Dr. Wang and his colleagues have developed a series of unique techniques for measuring the mechanical, electrical and field emission properties of individual nanotubes. The in-situ TEM technique developed by him is not only an imaging tool that allows a direct observation of the crystal and surface structures of nanocrystals, but also an in-situ apparatus that can be effectively used to carry nano-scale measurements (Science, 283 (1999) 1513). Using a custom-built specimen stage, the quantum conductance of a carbon nanotube has been observed in-situ in TEM, confirming the ballistic conductance and no-heat dissipation across a defect-free nanotube first published by de Heer’s group (Science, 280 (1998) 1744). A nanobalance technique and a novel approach toward nanomechanics have been (Phys. Rev. Letts. 85 (2000) 622). Their discoveries have attracted a great deal attention of the medium and professional community.

6. Dynamics of shape-controlled nanocrystals and nanocrystals self-assembly (Science 272 (1996) 1924; Science 316 (2007) 732-735; Nature, 420 (2002) 395)

    Nanosize colloidal platinum (Pt) particles are potentially important in industrial catalysis. The selectivity and activities of Pt particles strongly depend on their sizes and shapes. Much effort has been devoted to synthesize smaller size Pt particles for increasing the surface to volume atom ratio. Searching for techniques which can produce monoshape Pt particles has attracted a lot of interest because the chemical activities of Pt between {100} and {111} facets have distinct differences. Dr. Wang's collaboration with Prof. M.A. El-Sayed had led to a new technique based on colloidal chemistry for controlling the shapes and sizes of Pt particles at room temperature [Science 272 (1996) 1924]. Following this development, the growth mechanism of shape controlled Pt nanocrystals was studied using in-situ transmission electron microscopy. The shape transformation and melting behavior of the Pt nanocrystals were revealed for the first time.

    Wang and his collaborators have developed a novel electrochemical approach for successfully synthesizing tetrahexahedral (THH) Pt nanocrystals at high purity (>90%), which are a very unsual shape as defined by twenty-four facets of high-index planes ~{730} and vicinity planes such as {210} and {310} with a high density of surface steps and dangling bonds (Science 316 (2007) 732-735). The THH nanocrystals have demonstrated much enhanced catalytic performance of up to 400% per unit surface area than that of the Pt nanospheres or commercial catalyst. The success of synthesizing THH Pt nanocrystals by a square-wave electrochemical method starting from Pt nanospheres on amorphous carbon substrate presents a new approach for controlling the stability of nanocrystals defined by high-energy surfaces that have important applications in catalysis and fuel cells. This study demonstrates a novel approach for designing unusual and well-controlled particle shapes of noble metals, and it could be extended to other metals such as palladium. This research was selected as the 2007 highlights by ACS.

    The physical and chemical functional specificity of nanoparticles suggest that they are ideal building blocks for two- and three-dimensional cluster self-assembled superlattice structures in which the particles behave as well-defined molecular matter and they are arranged with long-range translational and orientational order. In 1996, Dr. Wang collaborating with the research group of Prof. R.L. Whetten obtained concrete experimental results demonstrating success of forming such superlattice structures using Au nanocrystals. Following this, Dr. Wang has concentrated on the preparation of size and shape controlled Ag and CoO nanocrystals. His group was the first to study the role of particle shape in determining the crystallography of 3-D assembling of nanocrystals and the structural stability and molecular bonding between nanocrystals. Dr. Wang's recent research has been focused on self-assembly of magnetic nanocrystals for ultrahigh density data storage media. His paper (Phys. Rev. Lett., 79 (No. 13) (1997) 2570-2573) won the 1998 Georgia Tech Sigma Xi Best Paper Award in a campus wide competition.

    Dr. Wang and his collaborators at IBM (H. Zeng and S. Sun) and University of Texas Arlington (J.P. Liu) have developed a process that incorporates FePt and Fe3O4 particles with different mass and radii ratio into binary assemblies (Nature, 420 (2002) 395-398). Controlled annealing results in metallic composites with magnetically hard and soft phase exchange coupled. The approach offers precise engineering control on the dimension of the components and their nanoscale interactions in the composite, rendering isotropic FePt-based nanocomposites with energy product value of 20 MGOe that exceeds the theoretical limit of 13 MGOe for single phase FePt.

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