Opto-electronic investigations on intermediate band solar cells

Our envisaged contribution in the current project is to attempt clarifying some of the issues affecting the efficiency in intermediate band solar cell structures and in which the intermediate band is due to the confinement of electrons in a layer(s) of quantum dots (QDs) embedded in a semiconductor of higher bandgap. We plan to achieve this through both experimental measurements and simulations. We aim to extend our previous studies carried out on QD-based devices in the dark to the case when these samples are under illumination. We expect, in particular, significant changes in the properties of deep-level defects under illumination compared to defects in the dark and we aim to achieve a clear understanding of the mechanisms behind these changes. We will use the already available techniques within SQU as well as the proposed, to-be-built, Optical-DLTS (ODLTS) setup to study some of the mechanisms highlighted above. Using ODLTS, in particular, one should be able to detect and study deep-level defects that are not possible to detect with the conventional DLTS in the dark.