Low-temperature MBE growth and characteristics of InP-based AlInAs/GaInAs MQW structures

Basic development steps towards low-temperature molecular beam epitaxy of InP-based AlInAs/GaInAs multiple quantum wells are presented. The achievement of unstrained material and the adjustment of 1.55 mu m emission necessitate modified growth conditions as compared to conventional growth. Single crystalline growth down to a temperature as low as 100 degrees C was successfully achieved as indicated by the appearance of superlattice peaks in the X-ray diffraction spectra as well as 300 K photoluminescence emission. The temporal development of transmission changes after optical excitation (pump-probe techniques) in the low-temperature material is predominantly governed by two recombination paths. Modelling of this bi-exponential decay on the basis of a three-level approach delivers the characteristics of the main trap incorporated in the quantum well material when grown at low temperature. The physical nature of this trap is attributed to AsGa as supported by results of beryllium doping.