: G 1240 (OTTO) Gallium oxide, GR 99.999% Cas no 12024-21-4 - used in vacuum deposition. It is useful for making semiconductor devices, gallium-alumina catalyst, gas sensors, luminescent phosphors and dielectric coatings of solar cells. G 1240 (OTTO) Gallium oxide, GR 99.999% Cas no 12024-21-4 - used as an evaporated material and sputtering target of 99.999% in dielectric films.