Optoelectronic characteristics and stability evaluation of Ba2TiMxO6 (Mx = Ge, Sn, Se, Te) p-type semiconductors as candidates for functional layers in optoelectronic devices

Abstract

Driven by the escalating demand for direct band gap semiconductors, this study elucidates for the first time the potential of Ba₂TiMxO₆ (Mx = Ge, Sn, Se, Te) perovskites in the realm of advanced photovoltaics and optoelectronics. The scope of this study spans the cutting-edge density functional theory computations of the structural, optoelectronic, and thermodynamic characteristics of specified materials. Additionally, it includes a comprehensive stability analysis that delves into their geometrical parameters (τ and μ), cohesive, formation, and decomposition energies, and their temperature-dependent phonon spectra, which provide critical insights into the stability of probed materials. The analyzed materials are from a notable class of direct gap semiconductors, as determined within the PBE–GGA framework, showcasing band gaps of 1.915, 2.315, 1.963, and 1.433 eV at 300 K for the investigated Ge-, Sn-, Se- and Te-bearing perovskites, respectively. Furthermore, band gap modulation with temperature is studied, denoting a stable optoelectronic behavior of these materials. Probing the optical characteristics reveals UV range optical spectra of absorption and extinction coefficients, dielectric constants, refractive indices, and optical band gaps. This study observed the enticing optoelectronic characteristics and robust stabilities of the materials studied, accentuating their potential as candidates for UV-based optoelectronic devices.