Effect of the implantation of Al$^+$ ions on the composition, electronic and crystalline structure of the GaP(111) surface

Nanocrystalline phases and GaAlP films are obtained by implanting Al$^+$ ions with $E_0$ = 1 keV at different doses on the surface of a GaP(111) single crystal, and their electronic and crystalline structures are studied. It is shown that the type and the lattice parameters of the three-component nanostructure are in good agreement with those for the substrate. The relationship between the band gap $E_g$ and the sizes of the nanocrystalline phases is studied. It is established that quantum-size effects arise in the Ga$_{0.6}$Al$_{0.4}$P nanocrystalline phases in the case of surface sizes $d$ of phases of less than 35–40 nm (3.5–4 nm thick).