Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 52: Nanostructures at surfaces: Wires, tubes

O 52.1: Vortrag

Mittwoch, 16. März 2011, 15:00–15:15, WIL B122

Surface and Interface Characterization of III-V Semiconductor Nanowires — •Rainer Timm, Martin Hjort, Edvin Lundgren, Lars Samuelson, and Anders Mikkelsen — The Nanometer Structure Consortium, Dept. of Physics, Lund University, Sweden

III-V Semiconductor Nanowires have attained strong interest due to their unique properties and tremendous possibilities for device application. They are characterized by an extreme surface-to-volume ratio, so that their surface properties or interface properties in core-shell nanowire heterostructures are crucial for the entire device behavior.

Recently, we have obtained first atomically resolved images of different InAs nanowire surfaces using scanning tunneling microscopy (STM) [1]. Here, we combine STM and scanning tunneling spectroscopy (STS) measurements to directly link local structural and electronic properties of InAs and InP nanowire heterostructures.

A promising application of InAs nanowires are high-speed metal-oxide-semiconductor (MOS) devices [2]. The exact chemical composition of the nanowire-oxide interface is crucial for the MOS device performance. We have therefore studied the reduction of the native oxide on InAs upon deposition of high-k dielectric thin films and the resulting interface properties using X-ray photoemission spectroscopy for planar InAs substrates [3] as well as for InAs nanowires. A clear reduction of various oxide states is observed, also depending on nanowire crystal structure and InAs surface orientation.

[1] E. Hilner et al., Nano Lett. 8, 3978 (2008). [2] S. Roddaro et al., APL 92, 253509 (2008). [3] R. Timm et al., APL 97, 132904 (2010).