Resonant photoemission spectroscopy for intermediate band materials

Resonant photoemission spectroscopy is used to study the intermediate-band material Cr doped ZnS. Using resonant photoemission, we show that the intermediate-band can be characterized, revealing the filling and specific orbital character of the states contributing to the resonant photoemission signal. We demonstrate that resonant photoemission spectroscopy is a powerful approach for understanding the origin of intermediate bands in doped ZnS. The methodology can be widely extended to a large variety of materials, providing useful information towards engineering of high efficiency intermediate band solar cells and of other optoelectronic devices.