A first-principles study of the III-IV-V semiconductor nanosheets

Alloying the III-V and IV-IV sheets leads to III-IV-V nano-composites, such as the BC2N sheet, having a lower band gap than their parent III-V counterparts while having higher cohesive energies. Unlike the well known BC2N sheet, the formation energy of the III-IV-V sheets with high Z atomic constituents is much low suggesting in favour of their experimental realisation. From first-principles hybrid density functional calculations, we report a family of group III-IV-V nano-sheets that have their electronic band gap lying between 0.13-1.0 eV, which is ideal for device applications. In particular, we compare the electronic, vibrational, mechanical and thermal properties of a set of III-IV-V sheets with their III-V and IV-IV counterparts. The cohesive energies of these III-IV-V sheets are found to be the intermediate of their parent III-V and IV-IV counterparts. The puckered geometry and the presence of heterogeneous bonds may result in low thermal conductivity (due to scattering of low energy phonons at the junction of the IIIV and IVIV chains) of these sheets.