A study of the effect of oxygen on the intensity of erbium photoluminescence in amorphous SiOx:(H, Er) films formed by DC magnetron sputtering

The effect of oxygen on the intensity of erbium photoluminescence at λ = 1.54 μm in amorphous a-SiOx:H(Er) films formed by dc magnetron sputtering was studied. The oxygen content in the gaseous phase ranged from 0.1 to 12 mol %, with other parameters of deposition remaining constant. Analysis of an a-Si:(H, Er, O) system showed that the range of homogeneity of amorphous a-SiOx:H(Er) is retrograde (T = const). The range of homogeneity can be conventionally divided into two portions, each of which should contain either of two differently charged [Er-O]n- and [Er-O-Si-O]m- clusters (m > n). This inference is confirmed experimentally: in the range of oxygen concentrations amounting to 5.5-8 mol % in the plasma, unusual associative processes take place probably directly above the growing film surface; these processes are caused by the appearance of [Er-O-Si-O]m- clusters in the plasma and at the surface. It is these processes that account for the intensification of erbium photoluminescence as the oxygen content increases above 5.5 mol %