Energy-band structure of chainlike polysilane(SiH2)nalloys

The energy-band structure for ideal polysilane ${\left(\mathrm{Si}{\mathrm{H}}_2\right)}_n$ is calculated using the Slater-Koster linear combination of atomic orbitals (LCAO) method. The interatomic matrix elements are estimated by using Harrison's approximate representation. From the calculated band structure we deduce that chainlike polysilane is a semiconductor having a wide direct band gap and that optical transitions are allowed. This is consistent with the experimental results showing a wide optical gap and highly efficient luminescence in novel Si: H alloys, consisting of many polysilane chain segments.