Structural, optical, and magnetic properties related to p-type InMnP:Zn epilayers with curie temperatures of Tc1 ∼ 50 K and Tc2 ∼ 291 K

Abstract

p-type InP:Zn epilayers were grown by using metalorganic chemical vapor deposition. After the growth of InP:Zn epilayers, Mn was evaporated on top of the InP:Zn epilayers by using a molecular beam epitaxy system. Then, Mn was diffused into the InP:Zn epilayers by annealing. InMnP:Zn epilayers were annealed at 600 °C for 60 s with Mn concentrations of both ∼1.5 and ∼3.0%. The optical transitions related to Mn appeared at 1.144, 1.187, and 1.212 eV and at 1.143, 1.179, and 1.205 eV for InMnP:Zn epilayers annealed at 600 °C for 60 s with Mn concentrations of ∼1.5 and ∼3.0%, respectively. Transitions related to Mn are noticeably activated due to an increase in the Mn concentration near 3.0% in comparison with transitions for Mn concentration near 1.5%. Clear ferromagnetic hysteresis loops were obtained for InMnP:Zn epilayers. The ferromagnetic hysteresis loop of the InMnP:Zn epilayers annealed with Mn concentration near 3.0% was bigger than that of epilayers with Mn concentration near 1.5%, and these results agree with the PL results that transitions related to Mn are remarkably activated upon annealing at Mn concentration near 3.0% in comparison with concentration near 1.5%. Ferromagnetic behavior persisted up Tc1 ∼ 50 K and Tc2 ∼ 291 K. Tc2 ∼ 291 K corresponds to MnP. Tc1 ∼ 50 K originates from intrinsic InMnP:Zn, which is caused by carrier-mediated ferromagnetism in the InMnP:Zn epilayer. We found that at Tc1 ∼ 50 K, a ferromagnetic semiconductor could be formed in a diluted magnetic semiconductor based on InMnP:Zn epilayers additionally co-doped with Zn.