Synthesis and investigation of transition metal oxide-doped heavy metal oxide glasses for their evaluation as large band gap semiconductors

Heavy metal oxide glasses have been investigated extensively due to their relatively low phonon energy, high refractive index, low glass transition and melting temperature, high dielectric constant and wide transmission range into the mid-infrared part of the electromagnetic spectrum. Owing to these numerous properties, heavy metal oxide glasses are promising materials for many opto-electronic applications such as optical data storage, lasers, sensors and spectroscopic applications. TeO2 and Sb2O3-based glasses have become prominent among the heavy metal oxide glasses. These glasses are suitable for doping and able to form ternary, quaternary or even quinary systems, which serves to increase the thermal and chemical stability of the glass. Additionally, it is known that the nature and concentration of the constituent oxides in multi-component systems substantially determine the thermal, physical, mechanical, optical, and electrical, etc. properties of the glass. Due to the variety of different oxidation states, transition metal oxides are able to enhance the electrical properties, increase the optical transmittance up to near infrared region and contribute the non-linear optical properties of heavy metal oxide glasses. In addition to this, heavy metal oxide glasses including transition metal oxides have been reported as mechanically rigid, non-wettable, chemically and thermally stable glasses. Therefore, investigation of transition metal oxide doped heavy metal oxide glasses is an interesting research area, there exist several studies on such glasses but novel studies are significant in terms of investigate and define the unknown futures of it. Therefore, in this study transition metal oxide doped heavy metal oxide glasses were investigated with the aim of characterization their thermal, physical, structural, kinetic and temperature dependent optical properties and evaluation of their potential to be used as transparent large band gap semiconductors. Within the scope of this thesis, glass samples in three different systems, MeO2-PbCl2-TeO2 (MeO2 = Bi2O3, Sb2O3, WO3, MoO3, ZnO), WO3-MoO3-TeO2 and, WO3-MoO3-Sb2O3, were synthesized. In the first studied system, PbCl2-TeO2 glass was selected as the main matrix and various transition metal oxides, such as Bi2O3, Sb2O3, WO3, MoO3, ZnO were chosen as tertiary components. As a result of thermal, physical, structural and temperature dependent optical investigations, WO3 and MoO3 were identified as the transition metal oxides providing superior optical features and two new glass systems with different glass formers (TeO2 and Sb2O3) were designed as WO3-MoO3-TeO2 and WO3-MoO3-Sb2O3. Then, by conducting detailed analyses, the effects of the transition metal oxides were investigated for two different glass formers, TeO2 and Sb2O3. Consequently, potential use of transition metal oxide containing heavy metal oxide glasses was evaluated as transparent large band gap semiconductors for opto-electronic applications. This thesis is the first detailed and systematical study on the synthesis of MeO2-PbCl2-TeO2 (MeO2 = Bi2O3, Sb2O3, WO3, MoO3, ZnO), WO3-MoO3-TeO2 and WO3-MoO3-Sb2O3 glasses and investigation of their thermal, physical, structural, kinetic and temperature dependent optical properties to evaluate their potential to be used as transparent large band gap semiconductors for opto-electronics. Therefore, this thesis will make a great contribution to the literature not only by determining the thermal, physical, structural and kinetic properties but also by investigating the effect of different transition metal oxide on temperature dependent optical properties of different heavy metal oxide glasses which have great potential to be used as transparent large band gap semiconductors for opto-electronic applications.