Aqueous Deposition of Ultraviolet Luminescent Columnar Tin-Doped Indium Hydroxide Films

摘要

Indium tin oxide (ITO) has attracted intense interest as the most important transparent conducting oxide (TCO) that sees wide use in many opto-electrbnic and photo-chemical devices. The goal of this study is to explore the possibility of depositing ITO thin films using a bioinspired aqueous deposition route as an alternative. On the surface of sulfonated-self assembled monolayers, Sn-doped indium hydroxide films are obtained via a hydrogen peroxide-assisted method. As a result, the as-deposited indium tin hydroxide films possess a single hexagonal phase of In(OH)_3· XH_2O (0 ≤ x ≤ 1) with Sn doping percentage of (1.7 ± 0.2) at % and a column-like hierachical microstructure. Structural, compositional and property studies, including electron microscopy, X-ray diffraction, photoelectron spectroscopy, optical transmittance, photoluminescence and four-probe conductivity measurements, are conducted. The possible mechanism based on oriented attachment is discussed for the film growth. Strong room temperature photoluminescence within the near UV range is observed in the case of Sn-doped, but not in the one of the pure In(OH)_3· xH_2O films. Annealing of the indium tin hydroxide films above 200℃ gives nanocrystalline Sn:In_2O_3 films with higher UV and visible transparency and electrical conductivity compared with those of pure In_2O_3 films. The influence of annealing atmosphere is investigated.