Yttrium-induced tunable bandgap for optical data storage applications

Abstract

Phase-change memory (PCM) relies on the characteristics of phase-change materials that exhibit slow resistance state changes and enable multilevel operation with minimal resistance drift. They are emerging as promising candidates for artificial intelligence applications inspired by neuroscience and require high volumes of data. However, achieving the necessary qualities, such as thermal stability and fast operation speed, simultaneously is still a major obstacle for PCM materials. The present study investigated the linear and nonlinear optical and electronic properties of Te_(1−x)(GeSe_0.5)Y_x (x = 0.05, 0.1, 0.15) thin films deposited via a thermal evaporation technique by structural characterization (using XRD), surface morphology analysis (using SEM), and elemental composition analysis (using EDX). Transmission spectra ranging from 500 to 2500 nm were obtained using a UV-visible spectrophotometer to determine the optical properties. The refractive index (n) and extinction coefficient (k) were also determined, and Tauc's relationship was applied to assess the optical absorption data. The absorption coefficient (α) was determined utilizing the Urbach relation. The Wemple–DiDomenico model was employed to calculate the nonlinear refractive index. Furthermore, the dielectric properties, loss tangent, and surface/volume energy loss functions were determined. The optical energy bandgap of the thin films revealed the allowed indirect transitions. The observed enhancement of the optical parameters suggested that the investigated composition is appropriate for different photonic applications.