The passivation layer of Al2O3 thin films prepared by liquid phase deposition on p-type (100) silicon substrate are investigated. The deposition solution of aluminum sulfate and sodium bicarbonate are used for Al2O3 thin films deposition. The concentration of the sodium bicarbonate in the deposition solution controls the deposition rate of Al2O3 thin films. The optimum condition is a pH value of deposition solution of 33 and annealing at 500 degrees C in N-2 atmosphere for 30 min. The effective minority carrier lifetime and fixed oxide charge density are 124.51 mu s and-2.15 x 10(12) cm(-2). Compared with bare silicon substrate, the effective minority carrier lifetime has increased by 41 times after the Al2O3 passivation layer deposition. (C) 2016 Elsevier B.V. All rights reserved.