Researchers at the Vienna University of Technology have combined two semiconductor materials, each only three atomic layers thick. Adding one semiconducting layer of the photoactive crystal tungsten diselenide to a layer of molybdenum disulphide, and “creating a designer-material that may be used in future low-cost solar cells.” Having worked with graphene, that two-dimensional, atom-thick material that promises much for structures, batteries and solar cells, Thomas Mueuller, assistant professor of photonics, and his team “acquired the necessary know-how to handle, analyze and improve ultra-thin layers by working with graphene.” The team applied their lessons learned with graphene to combining two ultra-thin semiconductor layers and are now studying their optoelectronic properties. Mueller explains, ““Quite often, two-dimensional crystals have electronic properties that are completely different from those of thicker layers of the same material.” In their present study, the Tungsten diselenide, a semiconductor consisting of three atomic layers; one layer of tungsten sandwiched between two layers of selenium atoms. Mueller adds, “We had …
Alchemy with Thin Film Structures
The blog has looked at several recent attempts to pull electricity from solar cells that have the ability to capture a broad range of light wavelengths. These are based on everything from layers of graphene and zinc nano-wires, to an exotic subwavelength plasmonic cavity, to straining solar cells to form wide bandgap funnels which capture light’s energy. Joining these efforts along with those of researchers in America and Germany, colleagues at the Vienna University of Technology are testing single atomic layers of oxide heterostructures, a new class of materials, to “create a new kind of extremely efficient ultra-thin solar cells.” Professor Karsten Held from the Institute for Solid State Physics at the University, explains, “Single atomic layers of different oxides are stacked, creating a material with electronic properties which are vastly different from the properties the individual oxides have on their own.” Researchers used large-scale computer simulations to discover that these layered structures “hold great potential for building solar cells.” …