Enhanced Physical Properties Of Indium Tin Oxide Films Grown on Zinc Oxide-Coated Substrates

Structural, electrical and optical properties of indium tin oxide or ITO (In۲O۳:SnO۲) thin films on different substrates are investigated. A ۱۰۰-nm-thick pre-deposited zinc oxide (ZnO) buffer layer is utilized to simultaneously improve the electrical and optical properties of ITO films. High purity ZnO and ITO layers are deposited with a radio frequency sputtering in argon ambient with plasma powers of ۱۵۰ W and ۳۰۰ W, respectively. After deposition, samples are annealed in a high vacuum furnace at ۴۰۰ ˚C. The effects of ZnO-coated substrates on the crystallinity and morphological properties of ITO films are analyzed by X-ray diffractometer, field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). X-ray diffraction patterns confirm the hexagonal wurtzite type polycrystalline structure of the ZnO films. FESEM and AFM analyses indicate that the surface morphology of the ITO films is affected by the ZnO buffer layer. Results also reveal that the roughness of ITO thin films is decreased in presence of the ZnO buffer layers. It has been found that ZnO incorporation promotes the crystallization of the ITO layer reduces its resistivity without deteriorating the optical transmittance.

Keywords:

ITO thin films , ZnO , buffer layer , Structural properties , Electrical and Optical Properties