A Comparative Study of Spin Coated Transparent Conducting Thin Films of Gallium and Aluminum Doped ZnO Nanoparticles

Abstract

Transparent conducting Ga:ZnO (GZO) and Al:ZnO (AZO) layers have been deposited by spin coating on glass substrates using crystalline nanoparticles redispersed in 1-propanol. The coatings have been sintered in air at 600°C for 15 min and then postannealed in a reducing atmosphere at 400°C for 90 min. The effect of Ga and Al doping on the structural, morphological, optical, and electrical properties of the obtained thin films was investigated. Both films were found to be crystalline with a hexagonal structure. A single step spin coated layer 52–56 nm thick is obtained. To increase the thickness and lower the obtained sheet resistance multilayers coatings have been used. The visible transmission of both layers is high (%). The influence of the sintering temperature and the optimum doping concentration was investigated. Five layers synthesized with doping ratio of 1 mol.% and sintered at 600°C and then submitted to reducing treatment in forming gas exhibited a minimum resistivity value of 7.4 × 10−2 Ω·cm for GZO layer and 1.45 Ω·cm for AZO coating.