P-Type Doping Effects on Band-Gap Energy for Ga0.5In0.5P Grown by Metalorganic Vapor Phase Epitaxy

Photoluminescence properties of Mg- or Zn-doped Ga 0.5 In 0.5 P grown by metalorganic vapor phase epitaxy were studied as a function of hole concentration ( p ). The band-gap energy ( E g ) value for Mg- or Zn-doped Ga 0.5 In 0.5 P, grown under a condition in which undoped Ga 0.5 In 0.5 P shows an anomalously low E g , showed a steep increase for p ∼>1×10 18 cm -3 . This anomalous behavior was attributed to the Mg or Zn diffusion-enhanced randomization of the previously observed naturally formed monolayer {1/2, 1/2, 1/2} superlattices on the column III sublattice.