Open Access Nano Express

A Novel Method to Fabricate Silicon Nanowire pn Junctions by a Combination of Ion Implantation and in-situ Doping

PratyushDas Kanungo1*, Reinhard Kögler2, Peter Werner1, Ulrich Gösele1 and Wolfgang Skorupa2

Author affiliations

1 Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle, Germany

2 Forschungszentrum Dresden, Rossendorf, FWIM, 01314, Dresden, Germany

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Citation and License

Nanoscale Research Letters 2009, 5:243-246  doi:10.1007/s11671-009-9472-x

Published: 8 November 2009

Abstract

We demonstrate a novel method to fabricate an axial pn junction inside <111> oriented short vertical silicon nanowires grown by molecular beam epitaxy by combining ion implantation with in-situ doping. The lower halves of the nanowires were doped in-situ with boron (concentration ~1018cm−3), while the upper halves were doubly implanted with phosphorus to yield a uniform concentration of 2 × 1019 cm−3. Electrical measurements of individually contacted nanowires showed excellent diode characteristics and ideality factors close to 2. We think that this value of ideality factors arises out of a high rate of carrier recombination through surface states in the native oxide covering the nanowires.

Keywords:
Nanowire; pn Junction; Ion implantation; In-situ doping; Electrical properties