Time-dependent quantum simulation of nanodevices

Vanderbilt University, Nashville TN

Investigators

Abstract

During the last few years impressive progress has been achieved in the development, fabrication and practical implementation of nanodevices to bridge the terahertz gap. The terahertz gap, lying roughly between 100 GHz and 30 THz, exists because the operating because the operating frequencies of transistors and lasers (typical semiconductor devices) do not overlap. The realization of THz nanodevices extends the range of electronics beyond the 100GHz barrier which is a major breakthrough leading to new transistors with higher speed, lower power usage and reduced heat generation. Besides important applications in security, biological sensing/imaging and high speedcommunications, the THz techniques allow probing electron dynamics in nanostructures observing electron propagation in real time. This research addresses the theoretical and and quantum simulation challenges of emerging new nanodevices operating at the terahertz (THz) region and beyond. The theoretical description and computational simulation of these systems is challenging because one should use time-dependent quantum mechanical approach with time-varying electromagnetic fields. This work represent the first systematic approach to studying the high frequency behaviour of nanodevices by time-dependent quantum simulations. The research will primarily focus on simulating and predicting the high-frequency behaviour of prototypical nanodevices, such as nanowires, carbon nanotubes, graphene, molecular device based field-effect transistors (FETs) and realistic (e.g. FINFET) transistors. The key contribution will be in providing quantitative descriptions of AC characteristics and high frequency properties of novel nanodevices including graphene, carbon nanotube, silicon nanowire transistors and nanoscale FINFETs. The results will be validated against experimental data through collaborations with experimental groups and will ultimately be cast in a form that will be suitable for incorporation in compact models for circuit modeling so that they can serve in the design of emerging technologies.