EFFECT OF SPUTTERING PRESSURE ON THE STRUCTURAL AND OPTICAL PROPERTIES OF ZNO FILMS DEPOSITED ON FLEXIBLE SUBSTRATE

Zinc Oxide (ZnO) has get attention because of its excellent optical transmittance approximately similar to 80%. A systematic study has been made of the effect of sputtering pressure on the structural and optical properties of the deposited ZnO films. ZnO thin films were deposited on plastic substrate by RF powered magnetron sputtering using ZnO disk with 99.99% purity. The RF power of 100 W and argon gas flow from 10 - 30 sccm was used to perform the sputtering process. The argon sputtering pressure was varied between 3 mTorr to 11 mTorr and the growth time is constant at 25 minute. The deposited ZnO thin films are characterized structurally and optically. Structural analysis using X-Ray Diffraction (XRD) show that all the films exhibit a (002) preferential orientation and the estimated grain size measured was varied from 24.5 nm to 29.8 nm. Surface Profilometer was used to measure the thickness and RMS of the deposited films where the thickness decrease from 900 nm to 600 nm and the root mean square (RMS) roughness increase from 4.97 nm to 11.45 nm. The optical transparency value that achieved from UV-Vis Spectrometer is over 80% in the visible range and the band gap energy is within 3.27 eV-3.29 eV range.