Ordering and disordering of doped Ga0.5In0.5P

The band gap of Ga0.5In0.5P is reported as a function of doping level and growth rate. The lowest band gaps are obtained for hole concentrations of about 2 × 1017 cm−3. For samples doped p-type above 1 × 1018 cm−3, the band gap increases dramatically, regardless of growth rate. This effect is shown to be the result of disordering during growth rather than a change in the equilibrium surface structure with doping. The doping level dependence of the band gap of Ga0.5In0.5P samples grown at higher and lower growth rates differs for selenium and zinc doping even though the effects of high doping are the same for both dopants.