Low Dimensional Nanoelectronics

Catalog description

This course will cover advanced concepts which are essential to understand modern state-of-the art electronic devices based on novel nanomaterials. The course is designed for experimentalists, material scientists, and device physicists who are interested to learn how carrier transport takes place in low dimensional semiconductors such as zero dimensional quantum dots, one dimensional nanotubes (CNT), quasi-one dimensional nanowires, and two dimensional nanosheets (graphene, MoS2). The course will begin with a review of semiconductor physics which includes Fermi-Dirac statistics, dispersion relationship (E-k), density of states, electron density, various definition of carrier velocities, and discussion on traditional drift-diffusion (DD) model for carrier transport. We will then adopt a bottom-up approach to understand current flow through a device with only one energy level, which will eventually lead to the formalism of Landauer-Datta (LD) transport model for ballistic conductors. The concept of quantum conductance and transport modes will be taught. We will also learn how to incorporate different scattering mechanisms into the LD model. The LD model will be used to understand current flow through a carbon nanotube (CNT), graphene, and MoS2. Next, the LD model will be extended to describe heat flow in nanomaterials which forms the basis of various thermoelectric phenomena such as the Seebeck effect, Peltier cooling, etc. The second part of the course will focus on the electrostatics and transport in ballistic and quasi-ballistic metal-oxide-semiconductor field effect transistors (MOSFETs). We will learn how to solve Poisson's equation self-consistently with LD model for Si MOSFET and extend it to ultra-thin-body-silicon-on-insulator (UTMSOI) FETs, FinFETs, CNTFETs, graphene and MoS2 FETs. The advantage of ultra-thin body channel material for MOSFET scaling and how nanomaterials help in overcoming short channel effects will also be taught. Concepts such as quantum capacitance limit will be introduced. Contact resistance and related issues will also be extensively taught. Various beyond Boltzmann novel device concepts tunnel FETs, phase change FETs, negative capacitance FETs, excitonic FETs, strain FETs for low power computing will be introduced. In the third part of the course we will learn multiple quantum mechanical effects related to transport in nanomaterials such as Quantum Hall effect, energy level broadening, and Coulomb Blockade phenomena in quantum dots. We will also learn multi-electron picture through Folk's Space in order to understand many body interactions. Finally, we will study the matrix version of Schrodinger equation to derive band-structure of different nanomaterials using nearest neighbor semi-empirical approach in orthogonal basis. Generalized transport equations will be obtained using Non Equilibrium Green's Function (NEGF) formalism. Students will be asked to do literature reviews on multiple topics taught in the course. They will also use their learning and solid foundation developed through out the course to execute group projects that are either exploratory in nature or relevant to the state-of-the-art technological problems of the semiconductor industry. This will prepare them for independent and innovative research.