Investigation of sol-gel derived Indium tin oxide thin films with poly(ethylene glycol) as an additive

Indium tin oxide (ITO) thin films, with/without poly(ethylene glycol) (PEG) additive, were deposited on either glass or oxidized silicon substrates by a sol-gel process. How the morphological, structural, optical, and electrical properties of the resulting ITO films changed with different processing parameters (heat treatment temperature and processing time), were investigated. X-ray diffraction (XRD) results showed that the introduction of PEG lowered the intensity peaks as compared to those from the undoped ones. SEM and AFM investigations indicated that the PEG-doped thin films also result in a flatter surface compared to the undoped. Electrical and optical testing revealed that the doping of PEG could lead to an increased optical transmittance rate (∼3-5%) for wavelengths 350-700 nm and a decreased sheet resistance. The ITO thin films prepared at low temperature has been employed as a gas-sensitive material for poisonous gas detection.