Photoluminescence of the Se and Si DX centers in (AlxGa1−x)0.5In0.5P (x<0.5) grown by metalorganic vapor phase epitaxy

Abstract

The near-infrared photoluminescence (PL) of Se and Si DX centers in (AlxGa1−x)0.5In0.5P grown by metalorganic vapor phase epitaxy has been demonstrated. Two luminescence peaks with energies of 1.16 and 0.96 eV were observed. The peak positions in PL spectrum were not shifted with various Al compositions (x) in (AlxGa1−x)0.5In0.5P (x<0.5). This phenomenon is similar to that found for the thermal activation energy of Se related traps (Ec−Et=0.28 eV determined by deep level transient spectroscopy measurements) and Si related traps (Ec−Et=0.4 eV) which also do not change with different Al compositions in AlGaInP. The intensity of these peaks increased with increasing net carrier concentration. In addition, the luminescence energies of these peaks are almost identical with those observed in AlxGa1−xAs (x from 0.07 to 0.4) doped with Se and Si. This observation contradicts the large lattice relaxation model, which predicts that the energy of these two luminescence peaks should change with various host materials due to different energy band structures. On the other hand, interpreted by the small lattice relaxation model, the 1.16 and 0.96 eV luminescence bands can be attributed to an internal transition between the excited DX state and its ground state of Se and Si DX centers, respectively. The luminescence energy is dependent on impurities themselves rather than the host materials, such as AlGaAs or AlGaInP.