Under density functional theory (DFT), a first principle analysis is conducted to pure, boron (B)- and phosphorus (P)-doped silicon-germanium nanosheets. It has been revealed that through doping, we can tailor both electronic and optical properties of SiGe nanosheet. The alternation in the energy gap due to the process of impurity substitution could be attributed to the SiGe nanosheet’s sensitivity to a particular dopant and means that by applying a particular impurity, we can adjust the electronic properties. Shifting in Fermi energy due to doping of B and P attributed to p-type and n-type semiconductors. The calculated Mulliken charge analysis revealed the existence of charge transfer between the atoms in the doped and undoped nanosheet. From the calculation of time-dependent DFT (TD-DFT), we confirmed that the maximum absorption wavelength of pure SiGe nanosheet is redshifted when it is doped with boron and phosphorus atom; the maximum absorption wavelengths shift from visible to infrared region. The theoretical examination of the electronic and optical properties of doped SiGe nanosheet opens a new path for silicon-germanium nanosheet applications over nano-electronics and optical systems.
