Abstract
We exploited novel two-dimensional (2D) carbon selenide (CSe) with a structure analogous to phosphorene, and probed its electronics and optoelectronics. Calculating phonon spectra using the density functional perturbation theory (DFPT) method indicated that 2D CSe possesses dynamic stability, which made it possible to tune and equip CSe with outstanding properties by way of X-doping (X = O, S, Te), i.e., X substituting Se atoms. Then systematic investigation on the structural, electronic, and optical properties of pristine and X-doped monolayer CSe was carried out using the density functional theory (DFT) method. It was found that the bonding feature of C-X is intimately associated with the electronegativity and radius of the doping atoms, which leads to diverse electronic and optical properties for doping different group VI elements. All the systems possess direct gaps, except for O-doping. Substituting O for Se atoms in monolayer CSe brings about a transition from a direct Γ-Γ band gap to an indirect Γ-Y band gap. Moreover, the value of the band gap decreases with increased doping concentration and radius of doping atoms. A red shift in absorption spectra occurs toward the visible range of radiation after doping, and the red-shift phenomenon becomes more obvious with increased radius and concentration of doping atoms. The results can be useful for filtering doping atoms according to their radius or electronegativity in order to tailor optical spectra efficiently.
Highlights
Low-dimensional nanostructures, monolayer honeycomb structures, attract much attention owing to their unique structure and exceptional properties, which differ from those of their bulk counterparts
Present studies concerned with two-dimensional (2D) materials are mainly focused on transition metal dichalcogenides (TMDs) [7,8,9,10] and single atom-thin sheets formed by group V atoms [11,12] to design novel nanoelectronic devices, such as field effect transistors and solar cells
The calculations of the geometric and electronic band structure indicated that puckered carbon selenide (CSe) is a direct band gap semiconductor with a gap of 0.905 eV, which opens up the possibility of exploring their application in optoelectronic devices
Summary
Low-dimensional nanostructures, monolayer honeycomb structures, attract much attention owing to their unique structure and exceptional properties, which differ from those of their bulk counterparts. The calculations of the geometric and electronic band structure indicated that puckered CSe is a direct band gap semiconductor with a gap of 0.905 eV, which opens up the possibility of exploring their application in optoelectronic devices. Monolayer CSe with puckered structure was verified to be a direct semiconductor with a band gap of 0.9 eV. The geometric, electronic, and optical properties of primitive CSe monolayer were systematically characterized based on comprehensive first-principles calculations. Our results show that X-doping (X = O, S, Te) is an efficient method to tune the band gap and optical properties of CSe monolayer and tailor its photovoltaic properties. By providing a deeper understanding of the novel properties of doping CSe monolayer, this work will pave the way toward rationally controlling the electronic and optical properties of monolayer CSe, opening up opportunities for a host of high-performance optoelectronic devices
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