Tailoring microstructure and optical properties of ZnO film on flexible substrates via homo-buffer layer engineering

ZnO films were deposited on flexible Teflon substrates using radio frequency (RF) magnetron sputtering, incorporating either as-deposited or annealed ZnO buffer layers. X-ray diffraction (XRD) analysis revealed that films grown with buffer layers exhibit enhanced c-axis orientation and significantly improved residual stress characteristics compared to non-buffered counterparts. Scanning electron microscopy (SEM) observations demonstrated that ZnO films on both ZnO-buffered and annealed-ZnO-buffered Teflon achieve smoother surfaces than those deposited directly on bare Teflon. Furthermore, photoluminescence (PL) spectra indicated that utilizing buffer layers, particularly with subsequent annealing, contributes to superior optical quality in the ZnO films.