Highly absorbent cubic structured silicon-monochalcogenides: promising materials for photovoltaic applications

Abstract

Exploring the high-efficiency materials for next-generation optoelectronic and photovoltaic applications is of great importance. In this article, we explore the potential of the newly designed cubic-structured Silicon-monochalcogenides (π-SiS, π-SiSe, and π-SiTe) for photovoltaic and optoelectronic applications. The density functional theory based full-potential linearized augmented-plane-wave plus local-orbital (FP-L(APW + lo)) method has been adopted to carry out this study. These materials possess cohesive and formation energies comparable to the other stable binary-chalcogenides reflecting their thermodynamic stability in the cubic structure. The results of electronic band structures reveal them indirect bandgap materials of bandgap energy 1.09, 0.88 and 0.47 eV for π-SiS, π-SiSe, and π-SiTe respectively. This new class of monochalcogenides has been found rich in several interesting features such as large density of states around the Fermi-level, relatively flat valence and conduction band edges, and heavier masses of charge carriers. As a result, the high absorbance of light (∼10 6 /cm) in the visible and lower ultraviolet (UV) regions has been observed. Similarly, a suitable optical reflectivity in the higher UV region was recorded which highlights their potential for application as a shield against UV radiations. This article further addresses the exciton binding energies, plasmon's energies, and low and high-frequency dielectric constants of these materials. Our results demonstrate the cubic-structured Si-monochalcogenides as thermodynamically stable and promising materials for cutting-edge optoelectronic and photovoltaic applications.