Achievement

Future THz electronic devices could be powered by solar cells. IGERT trainee Nicholas LiCausi in EE dept. along with physics students have worked on the growth of solar energy material. In solar cells, single crystal CdTe thin films are preferred over polycrystalline films. However, single crystal substrates for growing CdTe films are expensive. Current deposition techniques use amorphous substrates yielding polycrystalline textured films. IGERT co-PI Toh-Ming Lu’s team discovered that CaF2 nanorods grown by oblique angle deposition can form a biaxial texture on an amorphous substrate such as glass. Using the biaxial CaF2 buffer layer, the team is able to grow a biaxial CdTe film that is not single crystal but "quasi" single crystal. Electrical characterization of the biaxial CdTe film showed a very light (p-type) as expected. This new cost effective method to grow biaxial solar energy material is expected to yield better solar conversion efficiency than typical polycrystalline films.