A research group at the Norwegian University of Science and Technology (NTNU) has developed a method for making an ultra-high material efficient solar cell using semiconductor nanowires. If this is placed on top of a traditional silicon-based solar cell, it could potentially double the efficiency of today’s Si solar cells at low cost. “We have a new method of using gallium arsenide (GaAs) material in a very effective way through nanostructuring, so we can make solar cells much more efficient using only a tiny fraction of the material that is normally used,” says Anjan Mukherjee, a PhD candidate at the Department of Electronic Systems and the main developer of the technique. Gallium arsenide (GaAs) is the best material for making high-efficiency solar cells because of its extraordinary light absorption and electrical characteristics. It is commonly used to make solar panels mainly for use in space. However, high-quality GaAs solar cell components are quite expensive to make, which has driven a demand for techniques that cut the use of the material. In recent years, researchers have realized that a nanowire structure can potentially enhance solar cell efficiency compared to standard planar solar cells, even as less material is used.