1 Inorganic Nanocomposite Solar Cells by Atomic Layer Deposition (ALD) Investigators

This project is a fundamental study into the development of low-cost, thin film solar cells. It explores the fabrication of semiconductor nanocomposites for photovoltaics using nanostructured inorganic materials and atomic layer deposition (ALD). In thin film technologies, there exists a common problem with conversion efficiency due to poor materials quality: the photogenerated electrons and holes cannot travel very far before recombination (short free-carrier diffusion lengths) and are hence lost for power conversion. If the solar cell can be made using nanoscale heterojunctions, then every photogenerated carrier will have less distance to travel, and the problem of recombination can be greatly reduced. The proposed designs allow collection of all photogenerated carriers even in poor quality materials, thus making low cost deposition routes acceptable. We have performed modeling studies on single and multijunction device geometries which show that the negative effects of short minority-carrier lifetimes, namely high dark current, will be exacerbated by the large increase in junction area that occurs with nanostructuring. As a result, it appears that a good candidate for nanostructuring woul