Amazing Nano-Objects and Nanochemistry at Semiconductor Surfaces and Interfaces
19 Oct 2009



Patrick Soukiassian - (Paris-South University, Oray)


Silicon carbide (SiC) is a wide band gap IV-IV compound semiconductor having a strong interest in advanced electronic device/sensor applications, in nanotechnology and as a biocompatible material. Graphene is a single atomic layer of graphite that could be grown epitaxially on SiC, exhibiting unsurpassed transport properties and mechanical resistance. Cubic and hexagonal SiC and graphene surfaces are investigated by i) atom-resolved scanning tunneling microscopy and spectroscopy - STM-STS (electrons/photons)ii) synchrotron radiation-based core level/valence band photoemission spectroscopy, iii) grazing incidence x-ray diffraction, iv) infrared absorption spectroscopy, and v) low energy electron microscopy (LEEM). Strain is the leading driving force in surface organization and properties, and nanostructures self-formation.

Among some of the results, the following ones will be presented and discussed: 

  • Massively parallel self-organized Si and Ag/Si passive/active nanowires at SiC surface having exceptional characteristics, 
  • Temperature-induced semiconducting to metallic reversible SiC surface phase transition, 
  • sp ®sp3  diamond-type SiC surface transformation, 
  • sp2 SiC surface transformation & subsequent epitaxial graphene formation, 
  • Epitaxial graphene morphology, electronic properties and graphene/SiC interface, 
  • Atomic crack defects developing at SiC surface, 
  • The first example of H/D-induced semiconductor (clean and pre-oxidized SiC) surface metallization with an amazing isotopic effect. All these characteristics are unprecedented. They show novel aspects with SiC and graphene ability to be very promising materials in nanoscience and nanoelectronics and also offering exciting prospects for interfacing with biology.