Атмосферна корозія телекомунікаційних оптичних середовищ для халькогенідної фотоніки: кристалічний і склоподібний дисульфід германію

Abstract

Monograph is devoted to study of the relationship between structure and photoluminescent (PL) emission properties of bulk g-GeS2 glasses, having a different thermal history. In frame of the nano-heteromorphic glass-forming theory, by using the experimental, theoretical and spectroscopic methods this study is confirmed the hypothesis of the formation of mixed middle range order in g-GeS2 with ring fragments of two-dimensional layered, high-temperature β-GeS2 and three-dimensional, low-temperature α-GeS2 crystalline phases. Based on the theoretical calculations of the ring cluster vibrational spectrum and spectroscopic studies it was found that the synthesis condition used for preparation of germanium disulphide from melt temperature T2=1273 K with quenching rate of V2=1,5*102 K/s (hereafter denoted T2V2) compared with Т1V1 (Т1=1193 K, V1=102 K/с) and T3V2 (Т3=1373 K) where leads to an increase in the structural matrix of g-GeS2 (Т2V2) of fraction of a low temperature α-GeS2 clusters in comparison with their content in g-GeS2 (T1V1) and g-GeS2 (T3V2). During of the atmospheric corrosion of g-GeS2 (T2V2 ), the «violet» emission at 2.82 and 3.0 eV, characteristic of the PL spectrum quartz q-GeO2 solution in water and hydrated cluster emission are dominate in the photoluminescence spectrum of fractured surface. In the PL spectra of germanium disulphide obtained by synthesis conditions of T1V1 and T3V2, the emission in the green region of the spectrum is dominate, which is typical for GeOx nanowires. The correlation between the melt quenching conditions used for synthesis of germanium from Т3 and increasing content of «defective» five-membered rings with weak Ge-Ge bonds in the structural matrix of g-GeS2 (T3V2) and increasing of intensity the «red» emission from aged fractured surface of g-GeS2 (T3V2) at 1.60, 1.89 and 1.98 eV was detected. Such emission is characteristic for -OGeX3 (X=OGeH3) type defect in substoichiometric GeOx oxide. Luminescent properties of g-GeS2 and crystalline β-GeS2 are compared. The model of g-GeS2 surface degradation during atmospheric corrosion is proposed.