Effects of oxygen pressure on the growth of pulsed laser deposited ZnO films on Si(001)

Abstract ZnO thin films were prepared on Si(0 0 1) substrates using a pulsed laser deposition (PLD) technique and then their growth and properties were investigated particularly as a function of ambient O2 pressure during film growth. It was found that the microstructure, crystallinity, orientation and optical properties of the films grown are strongly dependent on the O2 pressures used. Completely c-axis oriented ZnO films are grown in a low O2 pressure regime (5×10−4–5×10−2 Torr), whereas a randomly oriented film with a much lower crystallinity and a rougher grained-surface is grown at an O2 pressure of 5×10−1 Torr. This deterioration in film quality may be associated with the kinetics of atomic arrangements during deposition. Our results suggest that ambient O2 pressure is an important processing parameter and should be optimized in a narrow regime in order to grow a ZnO film of good properties in PLD process.