Photocurrent polarization in long‐range ordered Ga0.5In0.5P

Photocurrent polarization properties near the band gap of long‐range ordered Ga0.5In0.5P have been investigated. The linearly polarized PC spectra of the ordered Ga0.5In0.5P show an absorption anisotropy for the [110] and [110] directions together with a large band‐gap reduction. The anistotropy in the PC spectra is due to a crystal‐field splitting at the valence‐band maximum in ordered Ga0.5In0.5P. The PC edge of the [110] polarization is lower at about 10 meV than one of the [110]. The polarization spectra defined by (I110−I110)/(I110+I110), where I110 and I110 are the PC signal intensities measured at the [110] and [110], respectively, show a single broad peak. The maximum polarization reaches about 50% at the energy of the transition between Γ6c and Γ4v, Γ5v. With increased sample temperature, the polarization maximum shifts to the lower energy side according to the change of the Γ6c‐Γ4v,Γ5v transition energy. Even at room temperature, a clear polarization signal was observed.