Flexible printed electronics: from materials characterization to device integration
Speaker: Dr. Tse Nga (Tina) Ng, Palo Alto Research Center (PARC)
Series: Electrical Engineering Departmental Seminar
Location: Engineering Quadrangle B205
Date/Time: Thursday, March 15, 2012, 4:30 p.m. - 5:30 p.m.
The development of mechanically flexible electronics has advanced rapidly in recent years and has enabled new form factors and functionalities in areas of displays and sensors, energy technologies, and bio-compatible electronics. Among the fabrication techniques for large-area flexible electronics, common printing tools such as inkjet and gravure press stand out as a low-cost method that allows rapid design changes, minimizes manufacturing waste, and has been proven across a range of relevant materials including nanoparticle dispersions, metal-oxide complexes, and organic semiconductors. Notably, the printing process is compatible with many substrates ranging from plastics to fibers, to potentially integrate electronics on any surface. At Palo Alto Research Center (PARC), we have developed all-additive inkjet printing processes to fabricate electronics on plastics. Some examples include flexible medical x-ray imagers and integrated logic-memory arrays. These applications required development of both individual device components as well as system integration.
In this talk, I will present the advantages and limitations of printed devices, and then discuss how to integrate the individual components together by using complementary organic thin-film transistor circuits. In addition to complementary circuits, I have also developed memory technologies, including ferroelectric and resistive memories as integral control switches. I will show how to tackle the challenges of device variations and stability in the printed systems. Device characterization and circuit simulations are carried out to achieve designs that tolerate the variations in printed devices, as well as to determine design rules for reliable thin-film electronic systems. The effect of printing fabrication on device and circuit performance is elucidated, in order to improve the reliability of the printing processes and accelerate the development of mechanically flexible electronics.
Dr. Tse Nga (Tina) Ng is a Member of Research Staff 2 with the Electronic Materials and Device Laboratory at Palo Alto Research Center (PARC). She joined PARC in 2006 where her research has focused on plastic electronics, such as the demonstration of bendable image sensors for x-ray medical imaging and sensor tapes for detecting head concussions. She is currently working on thin-film transistor devices and complementary logic circuits fabricated by printing techniques. Tina received her M.S. and Ph.D. in physical chemistry from Cornell University, NY, USA, working with Professor John Marohn on the development of force measurement techniques, such as cantilever magnetometry and electric force microscopy, in order to study nanoscale phenomena in organic semiconductors.