Disorder-free localization around the conduction band edge of crossing and kinked silicon nanowires

Date

2015

Authors

Keleş, Ü.
Çakan, A.
Bulutay, C.

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Source Title

Journal of Applied Physics

Print ISSN

0021-8979

Electronic ISSN

1089-7550

Publisher

A I P Publishing LLC

Volume

117

Issue

6

Pages

064308-1 - 064308-8

Language

English

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Abstract

We explore ballistic regime quantum transport characteristics of oxide-embedded crossing and kinked silicon nanowires (NWs) within a large-scale empirical pseudopotential electronic structure framework, coupled to the Kubo-Greenwood transport analysis. A real-space wave function study is undertaken and the outcomes are interpreted together with the findings of ballistic transport calculations. This reveals that ballistic transport edge lies tens to hundreds of millielectron volts above the lowest unoccupied molecular orbital, with a substantial number of localized states appearing in between, as well as above the former. We show that these localized states are not due to the oxide interface, but rather core silicon-derived. They manifest the wave nature of electrons brought to foreground by the reflections originating from NW junctions and bends. Hence, we show that the crossings and kinks of even ultraclean Si NWs possess a conduction band tail without a recourse to atomistic disorder.

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