First Generation (thick layers of crystalline silicon) and Second Generation (thin films of CdTe, CIGS, and related materials) PV devices are both well established in the marketplace, with well defined techniques for fabrication and characterization. Third Generation PV encompasses a wide diversity of materials and nanostructures and commercially viable technologies and means of fabrication are yet to be determined. Many of of the proposed structures have considerable microstructural variability that complicate interpretation of macroscopic device measures. The aim of this project is to develop idealized, three-dimensionally patterned templates that can serve as test structures to enable measurement of critical device and materials properties.
One of the most attractive properties of CdTe and CIGS for photovoltaic applications is their amenability to a variety of cost-effective fabrication methods, including sputtering, printing, and electrodeposition. We are developing three-dimensionally patterned photovoltaic test structures as well as fabrication processes including electrochemical deposition to enable the impact of geometry and internal defect structures on efficiency and broader photoelectrical properties to be determined.
To guide and interpret the experimental measurements we are developing models of light and charge transport within arbitrary 2D and 3D semiconductor and device geometries. These models will ultimately include the full effects of optical re-fraction and reflection that are relevant to all PV devices but play a particularly important role in 3D structures.