Enhancement of carrier concentration and spatial confinement in molecular-beam epitaxial Si and Be δ-doped GaAs by increasing As4/As2 flux ratio

We report the effects of changing As4/As2 flux ratio from an As cracking source on Si and Be delta-doped GaAs grown by molecular-beam epitaxy. It is observed that the carrier concentration increases as the As4/As2 flux ratio increases. The spatial confinement of carriers in the delta-doped induced potential well is also enhanced using high As4/As2 flux ratio. These effects are attributed to the enhancement of dopant incorporation by As4 during the delta-doping growth period.