Enhanced DFT predictions of the structural and optoelectronic properties of MoTe2 for high performance photodetection: Application to GW-based functionals and Hubbard U and V corrections

Abstract

Molybdenum ditelluride (MoTe2) is a promising two-dimensional material with ultimate prospective usage in high performance photodetection devices. In this study, we elucidate how this may be revealed and discuss how structural and optoelectronic properties of MoTe2 can be numerically accurately simulated since earlier experimental and theoretical studies on the bandgap of MoTe2 produced contradictory findings. In doing so, GW-based functionals using Hubbard U and V corrections are included in density functional theory (DFT) calculations to improve bandgap estimations. Interestingly, we reliably demonstrated that the estimated values of the bandgaps of 0.83 eV and 0.73 eV obtained, respectively, within this framework of DFT+U+V and GW, perfectly match the reported experimental results. Specifically, the quantum espresso simulation package is used for accurate DFT calculations allowing thereby a comprehensive investigation of the impact of the Hubbard U correction on the bandgap of MoTe2. Additionally, the optical absorption spectrum is examined for both GW and RPA levels of theory using the Yambo simulation tool, allowing for a readily distinctly identification of the material's light absorption spectrum. Contrasted by previous theoretical results, the random phase approximation (RPA) approach, which performs quite well in showing increased optical efficiency, reveals its effectiveness for obtaining appreciable gains in the values of the real, imaginary, refractive index, and extinction coefficient. The expected trends obtained with GW-based functionals using Hubbard U and V corrections approximate methods are encouraging, and altogether support ongoing attempts to optimize the physical properties of MoTe2 for high-performance photodetection systems by offering more precise bandgap predictions and valuable insights related particularly to the optical properties.