DFT Analysis of Structural, Electrical, and Optical Properties of S, Si, and F-Doped GeO2 Rutile

Abstract

This study examines the structural, electrical, and optical properties of S-, Si-, and F-doped GeO2 rutile with a 6.25% doping concentration using density functional theory (DFT) and the FP-LAPW method. The results show that the structural parameters align with previous studies. Doping reduces the band gap from 4.09 eV for pure GeO2 to 1.98 eV for GeO1.9375Si0.0625. The optical properties, including dielectric constant, conductivity, refractive index, and absorption spectrum, were analyzed up to 13 eV, revealing anisotropy along the zz (001) and xx (100) axes. These doped materials are promising for UV-sensitive photonic detectors, as they remain efficient even under sunlight exposure in the visible and infrared spectra. This could lead to the development of photodetection devices suitable for bright environments where traditional detectors are affected by sunlight.