Photoconductivity and dynamics of excitations in nanostructured and disordered semiconductors on ultrafast time scale

Ultrafast conductivity in nanostructured semiconductors and the related nanoscopic charge transport are the key issues for the development of optoelectronic and photovoltaic applications. These processes will be studied by optical pump – THz probe spectroscopy which constitutes a contact-free method accessing the relevant part of the spectrum. Complemented with ultrafast optical spectroscopy, with sample nano-topology inspection and with simulations of carrier motion it will reveal information about the length scales of the carrier localization, conductive coupling among nanoelements, energy landscape within nanostructured samples and local depolarization fields. Within the proposed project we will study nanoscopic transport of charges immediately after photo-excitation in disordered semiconducting systems oriented namely on solar cell technologies (nanostructured Si, Si nanowires, molecular wires, CdSe, CdS nanoparticles, etc.). We will develop adequate physical models and draw general conclusions about charge transport on the nanoscale.