MSE Ph.D. Defense – Xiaonan Wen

Date: Thursday, April 2nd, 2015

Location: Institute of Paper Science and Technology, 114

Time: 9:00-11:00 AM

Committee members:

Dr. Zhong Lin Wang (MSE, Advisor)

Dr. Meilin Liu (MSE)

Dr. Peter Hesketh (ME)

Dr. Gleb Yushin (MSE)

Dr. Zhiqun Lin (MSE)

Title: Piezotronics as an Electromechanical Interfacing Technology for Electronic and Optoelectronic Applications

Abstract:

Innovation on human-machine interfacing technologies is critical for the development of smart, multifunctional and efficient electronic/optoelectronic systems. The effect of piezotronics is a newly started field of study, which utilizes piezoelectric polarization that is mechanically induced inside a piezoelectric semiconductor to regulate electron transport across electronic contact interfaces. With the concept coined in 2006, many efforts have been contributed to studying the underlying physical mechanism of this effect as well as demonstrating various applications based on single nanowire piezotronic devices. This thesis selects ZnO as the material foundation and was started by firstly studying flexible, controllable and scalable synthesis methods for ZnO nanowires array and thin film. By replacing the use of random, individual nanowires with these materials, novel piezotronic and piezophototronic devices were designed, fabricated and tested to achieve the function of strain sensing, tactile imaging, piezo-enhanced photodetection and solar energy harvesting. The adoption of nanowires array and thin film materials over single nanowires leads to significant advantages in terms of scalable fabrication, industrial compatibility and broader functionality. By consistently going down this route, we believe that the field of piezotronics will eventually make revolutionary impact on MEMS, optoelectronics, multifunctional sensor networks, human-machine interfacing and so on.