Effect of the ambient field on the IV characteristics of nanowire resistors and junctions - A simulation study

Ambient field refers to the field lines outside the semiconductor that are caused by the potential difference between points on the semiconductor. We present a TCAD study of the effects of the ambient field on the IV characteristics of NanoWire (NW) resistors and junctions. The study covers different contact geometries, hilo as well as pn junctions, and practical bias range including the equilibrium condition; effects of varying the wire radius, length, doping and ambient dielectric constant are brought out. The NWs studied have radii≥15 nm and length≥500 nm for which classical models based on driftdiffusion transport are applicable. Simple qualitative explanations for various non-linear shapes of the IV characteristics are provided using field lines. An appealing analogy is presented for the rise in the carrier concentration of an undoped NW grown on a heavily doped substrate. The study is aimed at improving the understanding of nanoscale devices and proper interpretation of their experimental data. © 2011 Elsevier B.V.