The method of lanthanum fluoride passivating layer synthesis in the matrix of porous silicon by successive ionic layer deposition was elaborated and optimized. Luminescence and FTIR of obtained structures demonstrate the crucial role of the chemical composition of silicon nanocrystallite surface in the formation of radiative recombination channels and in the stability of porous silicon photoluminescence. The combination of high optical transparency of LaF3 layers and low recombination losses in silicon covered with such layers allows to recommend the lanthanum fluoride film as an effective passivating coating for silicon optoelectronics devices. (C) 2013 Elsevier B.V. All rights reserved.