Dense and porous zinc oxide (ZnO) thin films were deposited onto silicon substrates in vacuum and in 100 mTorr O-2 at room temperature by pulsed laser deposition using 15 ns krypton fluoride (KrF), lambda = 248 nm, laser pulses with laser fluence of 3 J cm(-2). The structural, morphological, optical and photoluminescence properties of the as-grown and annealed ZnO thin films were studied. O-2 background gas during deposition and post-annealing treatment were essential to obtain a crystalline structure and strong ultraviolet (UV) luminescence emissions. (c) 2005 Elsevier B.V. All rights reserved.