Semiconductor Nanowires: Building Blocks for Future Green Digital Computation

Prof. Jie Xiang
University of California - San Diego

Abstract:
For over a decade, nanotechnology has allowed rational synthesis of nanodot, nanowire and nanotube materials with different structure, composition, and with size control at the atomic precision. These nanoscale building blocks make it possible to assemble devices for a wide range of applications from nanoelectronics to ultra-sensitive medical sensors in the “Bottom-up” paradigm with promise for ever more compact, powerful and energy efficient devices that will impact our everyday lives. Underpinning applications of future nanotechnology is the understanding of a fundamental regime change - how electrons, photons and phonons populate and move around differently in such small dimensions compared to in bulk materials. In this talk I will use core/shell Ge/Si nanowire heterostructures as an example to illustrate how we can make a true 1D conductor where electrons only move in one direction, as well as create carriers without doping. These clean, high mobility nanowire channels could extend the roadmap for digital computation into the next a few decades. Fundamental barriers to lowering power dissipation in transistors can also be broken using nanoelectromechanical nanowire devices with the introduction of mechanical degree of freedom, which further extends the application of nanowire building blocks into high speed, low power consumption functionalities. Faster silicon usually means burning more power. In the last part I will discuss a new era of phononic engineering in nanowires to turn waste heat into power and to explore the greener side of silicon.

Brief Biography:
Dr. Jie Xiang joined the Department of Electrical and Computer Engineering and the Materials Science Engineering program at University of California, San Diego as an Assistant Professor in 2009. Prior to his appointment he was a KNI Prize postdoctoral fellow in the Kavli Nanoscience Institute at California Institute of Technology. He received the B.S. degree in physics from Peking University in China (2002), the A.M. degree in physics (2006) and the Ph.D. degree in chemical physics from Harvard University in 2007. His research interests include electron and phonon transport phenomena in nanostructured materials and the development of novel nanodevices for logic, sensing and energy harvesting applications. He is a recipient of the Materials Research Society Graduate Student Gold Award, the KNI Prize Postdoctoral Fellowship and NSF CAREER Award.