Absorption edge ofZn3P2

The experimental data of the ${\mathrm{Zn}}_3$ ${\mathrm{P}}_2$ absorption edge are analyzed for single crystals and thin films. The isotropic Kane band-structure model, with the introduction of a valence-level splitoff due to crystal-field interaction is used to calculate the absorption coefficient. The best fit to the experimental data has been obtained for the following parameters: energy gap, $E_g=1.51\mathrm{}$ eV; spin-orbit splitting, ${\Delta }_{\mathrm{so}}=0.21\mathrm{}$ eV; crystal-field splitting, ${\Delta }_{\mathrm{CF}}=0.04\mathrm{}$ eV; momentum matrix element, $P=4.7\mathrm{}\times {10}^{-10\mathrm{}}$ eV m; and heavy-hole effective mass, $m_{v1\mathrm{}}^{*}=0.22\mathrm{}{m}_0$, at 300 K.