Investigation of post-annealing indium tin oxide for future electro-optical device application

摘要

The nanostructure transformation associated with electro-optical properties via post-annealing of indium tin oxide film (ITO) is investigated by increasing post-annealing temperature in ambient oxygen. Although oxygen vacancy and activation Sn ions contribute to conductivity of ITO film, the oxygen vacancy inevitably reduces during posting annealing, but Sn-O related bonds are oppositely increased with IR absorption at 790 cm~(-1). Moreover, the sheet resistance of as-deposited ITO film 8.6 fl/sq increases to 47 Ω/sq as the annealing temperature rises to 500℃, the photoluminescence (PL) spectrum indicates that the oxygen vacancy plays a key role in dominating R_s in comparison with Sn-O bonds. The blue light transmittance of ITO film is slightly proportional to the annealing temperature due to phase crystallization enhancing band gap narrowing. Furthermore, as the annealing temperature rises beyond 500℃, the transmittance is compromised between the Burstein-Moss effect of high carrier concentration and nanostructure crystallinity. The oxygen deficient vacancy, instead of Sn-O related bonds, is a major contribution for ITO conductivity and transmittance