Tellurium, which is a semiconductor in its standard state, is used mainly as a component in type II/VI semiconducting- chalcogenides ; these have applications in electro-optics and electronics. Cadmium telluride (CdTe) is used in solar modules for its high conversion efficiency, low manufacturing costs, and large band gap of 1.44 eV, letting it absorb a wide range of wavelengths. Bismuth telluride (Bi 2 Te 3), alloyed with selenium and antimony, is a component of thermoelectric devices used for refrigeration or portable power generation.