Interface states in In0.5Ga0.5P/AlxGa1-xAs heterostructures grown by liquid phase epitaxy

We report the observation of deep traps localized near the heterointerface of the InGaP/AlGaAs structure grown by Liquid-phase epitaxy. In the case of low-quality InGaP/AlGaAs heterojunctions containing interface traps, the shape of capacitance-voltage (C-V) carrier profiles is affected by these deep states. To elucidate the characteristics of the interface traps, the deep-level transient spectroscopy (DLTS) measurements are performed. It is found from the DLTS measurements that the electron traps distributed over the energy range of 0.4-0.8 eV below the conduction-band minimum are presented at the InGaP/AlCaAs heterointerface. These interface traps are found to induce an abnormal dependence of C-V profiles and the conduction-band offset on the temperature. The origin of these states and their influence to the electrical and optical properties are also discussed. (C) 1997 American Institute of Physics.