Optimum Indium Concentration for Growth of 1.3μmInAs/In_xGa_1-xAs Quantum Dots in a Well

Five InAs/In_xGa_1-xAs quantum dots in a well (DWELL) with different indium concentration x are grown by solid source molecular beam epitaxy. The high quantum dot density is observed in the InAs/In_0.3Ga_0.7As DWELL. The photoluminescence (PL) experiments indicate that the ground state peaks of
InAs/In_0.15Ga_0.85As and InAs/In_0.22Ga_0.78As DWELLs shift to 1.31 and 1.33μm, respectively. The optical properties are investigated by using the PL and piezoreflectance spectroscope methods. An abnormal blue shift has been observed with the further increase of x from 0.22 to 0.30.