ELECTRICAL, OPTICAL AND ANNEALING CHARACTERISTICS OF ZNO-AL FILMS PREPARED BY SPRAY PYROLYSIS

Transparent conducting thin films of aluminium-doped zinc oxide have been prepared by spray pyrolysing a solution of zinc acetate and aluminium chloride. The effect of changing the aluminium-to-zinc ratio from 0 to 6 at.%, substrate temperature from 300 to 500-degrees-C and spray rate from 5 to 16 ml min-1 has been thoroughly investigated. As-deposited films have very high resistivity and high visible transmission. Annealing of the as-deposited film in a hydrogen atmosphere leads to a substantial reduction in resistivity without affecting the optical transmission. The best films have a resistivity of about 10(-3)-OMEGA cm and a visible transmission of about 85%. Preliminary studies indicate that the films are stable in silane and silane plus hydrogen plasma.