Dr. Wang is a Regents' Professor and College of Engineering Distinguished Professor at Georgia Tech. He has authored and co-authored four scientific references and textbooks, published over 450 peer reviewed journal articles, 43 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 15,000 times. The H-index of his publications is 58. 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.

From Nanogenerators to Nano-Piezotronics

Zhong Lin Wang
School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta USA

Developing novel technologies for wireless nanodevices and nanosystems are of critical importance for in-situ, real-time and implantable biosensing, biomedical monitoring and biodetection. 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 (such as body movement, muscle stretching), vibration energy (such as acoustic/ultrasonic wave), and hydraulic energy (such as body fluid and blood flow) into electric energy that will be used to power nanodevices without using battery. We have demonstrated an innovative approach for converting nano-scale mechanical energy into electric energy by piezoelectric zinc oxide nanowire (NW) arrays [1-3]. We have recently developed DC nanogenerator driven by ultrasonic wave [4], which is a gigantic step towards application in practice.

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. Based on this principle, piezoelectric-field effect transistor [5], piezoelectric gated diode [6], sensors and resonators have been fabricated, which are the fundamental components of nano-piezotronics . Piezotronics is a field of using piezoelectric-semiconducting coupled property for fabricating novel and unique electronic devices and components [7].

[1] Z .L. Wang and J.H. Song   " Piezoelectric Nanogenerators Based on Zinc Oxide Nanowire Arrays", Science , 312 (2006) 242-246.

[2] P.X. Gao, J.H. Song, J. Liu and Z.L. Wang "Nanowire Nanogenerators on Plastic Substrates as Flexible Power Source", Adv. Mater. , 19 (2007) 67-72.

[3] J.H. Song, J. Zhou, Z.L. Wang "Piezoelectric and semiconducting dual-property coupled power generating process of a single ZnO belt/wire - a technology for harvesting electricity from the environment", Nano Letters, 6 (2006) 1656-1662.

[4] X.D. Wang, J.H. Song J. Liu, N.S. Xu and Z.L. Wang "Direct current nanogenerator driven by ultrasonic wave", Science , 316 (2007) 102-105.

[5] X.D. Wang, J. Zhou, J.H. Song J. Liu, N.S. Xu and Z.L. Wang "Piezoelectric-Field Effect Transistor and Nano-Force-Sensor Based on a Single ZnO Nanowire", Nano Letters , 6 (2006) 2768-2772.

[6] J. H. He, C.H. Hsin, L.J. Chen, Z.L. Wang "Piezoelectric Gated Diode of a Single ZnO Nanowire", Adv. Mater. , 19 (2007) 781.

[7] Z.L. Wang "Nano-piezotronics", Adv. Mater., 19 (2007) 889.