Nanoscale device modeling: From MOSFETs to molecules
This thesis presents a rigorous yet practical approach to model quantum transport in nanoscale electronic devices. As conventional metal oxide semiconductor devices shrink below the one hundred nanometer regime, quantum mechanical effects are beginning to play an increasingly important role in their performance. At the same time, demonstration of molecular switches has generated considerable interest in the emerging field of molecular electronics. Understanding electronic transport in nano-devices and molecules using rigorous physics based models is critical in order to design and fabricate such structures. Our approach is based on the non-equilibrium Green's function (NEGF) formalism which is rapidly gaining acceptance as the method of choice to treat quantum transport in nanostructures. We use our method to treat a few nanoscale devices of current interest, namely, a dual-gate silicon nanotransistor (effective mass model), a three terminal molecular device (semi-empirical atomic orbital model) and two terminal molecular wires (rigorous ab initio atomic orbital model). The results provide useful insights into the underlying physics in these devices. Several important features like charge transfer, self-consistent band lineup, I–V characteristics, voltage drop etc. are analyzed and explained. ^
Major Professor: Supriyo Datta, Purdue University.
Engineering, Electronics and Electrical|Physics, Condensed Matter