Abstract

This paper reports the first results obtained on calcium gadolinium oxoborate GdCa₄O(BO₃)₃ (GdCOB) thin films grown on silicon coated with amorphous silica at high temperature by pulsed-laser deposition (PLD). It was found that the chemical composition (i.e. Ca/Gd ratio) depends critically on the oxygen pressure used during pulsed-laser deposition (PLD) experiments. The crystallization of thin films about 500 nm thick required a high temperature substrate (750 °C) during the PLD process followed by a post annealing treatment at 800 °C in an oxygen atmosphere. Under these conditions, the layers are polycrystalline and no texturation features have been found. The surfaces of the films are smooth (average roughness: 5-6 nm) with only a few particles or droplets. The refractive index of the films is estimated to be 1.746 at 633 nm, in agreement with the bulk GdCOB value.