“Adventures with Carbon Nanotubes: History, Materials Science, Device Physics
and Circuit Applications”
Deji Akinwande, Stanford University
Wednesday, Feb. 25, 1 p.m., NSERL 3.204
Abstract: Carbon nanotubes (CNTs) and fibers have been one of the major materials in the history of modern civilization over the past 120 years, initially for applications in electric lighting, and subsequently as performance composites in the aerospace industries. Over the last decade, the rediscovery of carbon nanotubes as exploratory nanomaterials has led to an intense investigation of their properties for many applications, including electronic technology, sensor technology and green technology. These technologies promise improved devices and products that would enhance our quality of life. In the past five years, challenges regarding circuit performance, high-density aligned material synthesis and device physics have been pressing issues in advancing CNT electronic technology. Will nanotube transistors and circuits be widely adopted in the mainstream if accurate analytical and compact models are not available? Equally important is if CNT VLSI technology can even become a reality if it cannot be synthesized with high-density on arbitrary wafer sizes? This broad talk will begin by providing an overview of the discretized history of invention, and re-discovery of carbon nanotubes. Subsequently, we elucidate on our recent progress in two key areas of fundamental significance, including:
1. Comprehensive carbon nanotube analytical device physics and modeling with demonstrated validation by state-of-the-art experimental nanotube devices. The validated analytical model was enabled by innovations arising from a sustained focus on the solid-state physics of CNTs, including properties such as the quantum capacitance, surface potential and the relatively new device physics of drain optical phonon scattering, leading to strong agreement between model and experiments in all regions of transistor operation. Fundamental parameters such as bandgap are directly extractable from electrical measurements. Performance comparisons with existing and future ITRS CMOS will be highlighted.
2. Synthesis of perfectly aligned carbon nanotube growth on crystalline quartz substrates using iron catalysts. Systematic surface science studies of the catalyst species using atomic force microscopy, X-ray photo-electron spectroscopy and scanning electron microscopy reveals the dynamics of the surface chemistry and physics leading to the first demonstration of high-density aligned growth on a full-wafer, a significant step forward for future CNT technologies.
In addition, we address the future of carbon nanotubes for electronic applications. Are they going to be a primary dominant technology that perhaps competes directly with silicon? Or will they exist in other forms?
Biography: Deji Akinwande is a doctoral candidate in electrical engineering at Stanford University. He has completed his thesis research and is currently conducting post-Ph.D. research on nanomaterials for integrated wireless bio-sensors. His doctoral research focused on the applications of carbon nanotube materials, leading to eight peer-reviewed publications. He is currently under contract with Cambridge University Press to co-author the first textbook on “Carbon Electronics and Device Physics.” He is a co-inventor of a commercial high-frequency interconnect, invented an ultra-low noise amplifier while at TSMC, and won the Cheesy Award from Prof. Thomas Lee for outstanding circuit design. He is a recipient of Ford Foundation and Alfred P. Sloan fellowships and was honored to receive the inaugural Stanford University future-faculty DARE fellowship.
