Structural, vibrational, photoluminescence and photo electron spectroscopic properties of rf magnetron sputtered ZnO films grown on unheated glass substrates are discussed. Variations in the c-axis orientation, average crystallite size, residual stress, and presence of disoriented grains, with varying oxygen content (40%-100%) during film growth are found to correlate with variation in the E-2(high) and A1(LO) modes of the Raman spectra. Room temperature photoluminescence (RTPL) spectra exhibit a characteristic splitting in the near-band-edge emission (NBE) with three emission peaks (around 355, 386 and 395 nm) under an excitation wavelength of 290 nm. The blue emission (443-455 nm) is significantly controlled by oxygen vacancies and seen in films grown under 80% oxygen content. Quenching of NBE emission, for films prepared under oxygen rich ambient, is caused by the increased non-radiative recombination centers owing to reduced size of ZnO nano-crystallites. The shifts in the optical band gap of films grown under different oxygen content supplement the observed changes in the nano-crystallite size and luminescence properties. X-ray photoelectron spectroscopy confirms the fractional changes in the oxygen vacancy content in films deposited under different oxygen content in the sputtering gas. (C) 2016 Elsevier B.V. All rights reserved.