Thickness effect on luminescent properties of sol–gel derived ZnO thin films

We studied the photoluminescence (PL) characteristics of ZnO thin films grown by sol–gel spin-coating technique. The ZnO thin films are preferentially oriented along the c-axis perpendicular to the substrate. The radiative recombination of donor-bound excitons dominates the low-temperature PL spectra. Defect-related transitions enhance as thickness decreases. The lineshape of room-temperature PL spectra from sol–gel deposited ZnO thin film is greatly influenced by exciton–phonon interaction, which is governed by defects in the thin films.