A semiconductor is a material with electrical conductivity intermediate in magnitude between that of a conductor and an insulator. Semiconductor materials are the foundation of modern electronics, including radio, computers, telephones, and many other devices. Such devices include transistors and digital and analog integrated circuits. Transition metal oxides also fill this category of materials. But these materials are also relatively rare and expensive. Harnessing the energy of sunlight can be as simple as tuning the optical and electronic properties of metal oxides at the atomic level by making an artificial crystal or super-lattice sandwich, says a Binghamton University researcher in a new study published in the journal Physical Review B which uses more ordinary and commonly available metals.