Nanoscience and Nanotechnology: Basic Science and Applications of Nanoparticles
Semiconductor nanocrystals are molecular-like semiconductor materials composed of hundreds to thousands of atoms, intermediate between a solid and a molecule. In this regime fundamental properties depend
on size, composition and shape. Due to the tunable properties of such nanostructures, they show great potential for use as building blocks of devices in nanotechnology. I am interested in preparation,
characterization, in the optical and electronic properties of nanocrystals and in developing new applications based on their unique properties. Special attention is devoted to nanostructures of
technologically relevant II-VI and III-V semiconductors spanning the range from properties of single nanocrstructures to collective effects in their assemblies. In recent years we focus on development of
hybrid nanoparticles, composed of disparate elements such as metal-semiconductor hybrid nanoparticles. Such systems manifest a unique model for the semicoductor-metal interface on the nanoscale. The
combination of such diverse materials on one nanoparticle, increases the functionality of the system. For example, metal tips on semiconductor nanorods offer anchor points for self assembly and electrical
connections. The high level of control of nanoparticle synthesis and deep understanding of the physico-chemical properties achieved in recent years opened avenues for application of such nanoparticles in
solar energy harvesting, which is also of central interest for us.
1. Synthesis and characterization of novel semiconductor
nanocrystals and nanostructures and their assemblies:
Developing the bottom-up approach for preparing semiconductor nanocrystals and nanostructures with tailored properties.
Development of multi-component hybrid nanocrystals such as gold-tipped nanorods ('nano-dumbbells').
Synthesis of new semiconductor nanocrystals and nanorods with special focus on III-V semiconductors.
Growth of heterostructured nanorods and and nanocrystals including core/shell nanocrystals and seeded nanorods exhibiting high emission quantum yield.
Studies of self assembly of nanocrystals.
2. Size dependent optical and electronic properties of nanocrystals:
Evolution of the electronic, optical and electrical properties with size from the molecular regime to the solid state.
Study of the size dependent level structure using optical spectroscopy, tunneling spectroscopy and transport spectroscopy.
Development of new methods combining optical and tunneling spectroscopy to investigate semiconductor nanocrystals.
Single electron tunneling phenomena in nanocrystals and nanorods.
Time dependent electronic spectroscopy of semiconductor nanocrystals.
3. Single nanostructure microscopy and spectroscopy:
Scanning probe microscopy including optical microscopy and atomic force microscopy and their application to study of semiconductor nanocrystals and nanorods.
Developing novel scanning probe methods combining optical and force microscopy to study single nanocrystals.
Apertureless near field spectroscopy and microscopy of nanostructures.