Gallium oxide (Ga₂O₃) is considered to be one of the most ideal materials for application as thin-film gas sensors at high temperatures. Gallium oxide (Ga₂O₃) is an electrical insulator at room temperature and semiconducting above 400 ^oC. Chemical vapour deposition (CVD) is the most practical method for preparing thin-films for large-scale applications. The versatility of metal alkoxides as precursors to metal oxides via CVD processes is widely recognised; they are easy to prepare and purify and are intrinsically non-corrosive. A range of new gallium alkoxides incorporating functionalised alkoxides have been prepared (Scheme 1).  

Scheme 1

Thin films of Ga₂O₃ have been formed on glass by low pressure (LP)CVD at 600 ^oC and aerosol assisted (AA)CVD using a molecular precursor or from the in situ reaction of Et₃Ga or [Ga(NMe₂)₃]₂ and excess alcohol. The resulting films were analyzed by powder XRD, XPS, SEM and EDAX, which showed low levels of contamination from carbon. Gas sensing experiments indicated that the films responded best to a reducing gas at 450 ^oC.