Bandgap engineering in Si1-xCx by substitutional doping: First-principle calculations

In this paper, a novel approach is presented for the first time to increase the energy gap of Si-based material by doping carbon atoms into Si-based material structures. The structural electronic properties and mechanical properties of Si1-xCx (x = 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4) are investigated using a first-principles calculation method. Bandgaps of the Si1-xCx shells were found to have, respectively, quadratic relationships with the Carbon content (x). Meanwhile, the electronic bandgap of Si-based material can be increased by 0.334 eV due to the carbon substitutions. The optimal structure is Si0.7C0.3 and the elastic constants and phono calculations reveal that Si0.7C0.3 is mechanically and dynamically stable. Finally, two different heavy doped Si0.7C0.3 have been investigated and the results indicate that the p-type and n-type doped Si0.7C0.3 do produce shallow levels. This study can be a theoretical guidance to improve the bandgap of Si-based semiconductors. In addition, Si0.7C0.3 show superior bandgap and material properties enabling Si0.7C0.3 power device operation at higher temperatures, voltages than current Si-based power semiconductor device.