Effect of sulfur concentration on electronic properties of h-BN monolayer: a computational study

The hexagonal boron nitride (h-BN) monolayer, owing to its applications in biological materials, multi-function composites and optoelectronic devices, has drawn a lot of interest recently. Here, the structural and electronic characteristics of monolayered h-BN sheets doped with sulfur (S) are theoretically explored through density functional theory calculations. Our primary focus was on how the dopant site and concentration is responsible for geometry and energy gap variation. The interatomic distances and position of the substitutional S atoms control the position of defect-related intermediate bands and the band gap of doped material. Strikingly, an indirect bandgap of doped system shows semiconducting behavior, which is narrower than the one for pristine sheet. Different structural arrangements (hexagonal and rectangular) of S defects at the BN monolayer provide a general design for defect engineering which is congenial for its applications in deep UV optoelectronic, electronic, and transistor-based devices.