Synthesis and Characterization of the Quaternary Chalcogenide Glass Bi1Te15Se84xP for ITS Application in Various Fields

Abstract

This thesis presents a systematic investigation into the synthesis, characterization, newlineand functional analysis of selenium-based multicomponent amorphous and crystalline newlinematerials, along with a critical review of one-dimensional photonic crystals (1D PhCs) newlinefor optical limiting applications. Bulk and thin film samples of Bi1Te15Se84and#8722;xPbx (0 and#8804; x and#8804; newline8) were fabricated using conventional melt-quenching and thermal evaporation newlinetechniques. Detailed structural analysis using X-ray diffraction (XRD), scanning newlineelectron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and Raman newlinespectroscopy was carried out to understand the influence of lead (Pb) incorporation on newlinethe microstructural, morphological, and vibrational properties of the materials. XRD newlinepatterns revealed that pure thin films were amorphous, whereas Pb-doped compositions newlineexhibited crystalline nature with distinctive snowflake-like morphology as observed in newlineSEM images. newlineThermal behavior was investigated using differential thermal analysis (DTA) at newlinevarious heating rates. Key thermal parameters such as activation energy for glass newlinetransition and crystallization, fragility index, and Hruby s parameter were determined newlineusing Kissinger s and Augis Bennett s methods. The alloys demonstrated a good glass newlineforming ability and high thermal stability, as evidenced by the reduced glass transition newlinetemperature and high activation energy values, thus qualifying them for applications in newlinephase-change memory and optoelectronic devices. newlineIn parallel, the thesis critically reviews the role of 1D photonic crystals as newlinepromising optical limiters. Emphasis was placed on structures employing rare earth newlinemetals, semiconductor materials, nanocomposites, and phase-changing materials as newlinedefect layers. The integration of such defect layers within 1D PhC structures can newlineefficiently reflect high-intensity laser radiations, thus protecting sophisticated optical newlinesensors and devices. Moreover, the employment of quantum dots and nanocrystals newlinewithin defect layers has been recognized as a means to