Studies on Diverse Properties of Various Semiconducting Materials for Optoelectronic Applications

Abstract

II-VI and IV-VI alloys have always been an interesting field of research due to their wide range of applications especially in the optoelectronics domain. II-VI and II-VI-O ternary and quaternary alloys have applications in optoelectronic and solar cells applications. II-VI and II-VI-O alloys undergoes significant amount of band gap reduction thereby leading to its application in near and mid- infrared regions. But, the incorporation of Cadmium (Cd) and Oxygen (O) in II-VI Zinc-Telluride (ZnTe) alloys also introduces high band gap reduction ,improved spin-orbit split off energy, lowered strain profile in the material. This results in significant amount of up gradation in the electronic properties of the alloys. The co-doping of Cd and O in II-VI alloys is expected to reduce strain in the material. One of the primary sections of this thesis focuses on investigating the effect of incorporation of both Cadmium and Oxygen in ZnTe substrate leading to the formation of Zinc Cadmium Telluride (Zn1-xCdxTe) and Zinc Cadmium tellurium Oxide(Zn1-xCdxTe1-yOy) alloys. Various parameters have been calculated for the ternary and quaternary material like lattice constant, band gap, band offset variation, strain profiles, sub-band interactions, Ecb, Evb, wavelength variation, spin-orbit split off energy. The calculation of such parameters has been performed employing semi-empirical modelling techniques like Vegard s law and Interpolation method. Hence, a comparative study between Zn1-xCdxTe and Zn1-xCdxTe1-yOy alloys with respect to various parameters have been performed. Thereby, claiming superiority between the two in terms of optoelectronic applications. A comprehensive study of electronic and optical properties of PbxSn1-xO2 (x = 0.125, 0.25 and 0.375) have been performed utilizing PBE-GGA + TB-mBJ scheme employing WIEN2K package under DFT formalism. The lattice constant parameters obtained for PbxSn1-xO2 were observed to be invariant in comparison with rutile SnO2. The DoS (Density of States) profile of PbxSn1-xO2 determine