Off-Equilibrium Doping of Semiconductor Nanowires

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

Aimed at controlling the doping of nanowires to the level exceeding the thermodynamical equilibrium limit, the research objectives of this award are: 1) to demonstrate extreme doping levels in semiconductor nanowires comparable to those in the bulk, 2) to show uniform activated nanowire doping along the radial direction; and 3) to break the natural doping propensity of nanowire materials. Outreach activities are proposed to promote diversity in the nanoscience sector by the training and mentoring of scholars from diverse backgrounds. The approach will be to employ an extremely off-equilibrium technique combining ion implantation and pulsed-laser processing to control the doping kinetics and physics in nanowires synthesized by the vapor-liquid-solid method. The proposer?s preliminary results have shown superiority of this technique on all technical metrics in doping silicon nanowires compared to other equilibrium methods. Single-nanowire devices will be fabricated for evaluation of activated dopant concentration and distribution. Finite element modeling will be performed to simulate the electrostatics and electrodynamics of doped nanowires for analyzing experimental data. If successful, the research will benefit society at large by laying a materials foundation for a new generation of microelectronic and optoelectronic technologies. A new strategy will be discovered to dope semiconductor nanowires at unprecedentedly high concentrations and uniform distribution. The natural doping propensity and disparity of many technologically important semiconductors will be overcome. The achievement would produce significant advancements in the understanding of defect physics and kinetics in nanoscale materials. Demonstration of such doping strategy will promote innovations in semiconductor nanostructure synthesis and device processing. New knowledge will be gained concerning the materials science and processing at the nanoscale.