Characteristics of high responsivity 8.5 μm InGaAs/InP QWIPs grown by metalorganic vapour phase epitaxy

Higher responsivity of quantum well infrared photodetectors based on In0.53Ga0.47As–InP material system compared to the well established GaAs–AlGaAs material system is analyzed. It is shown that the higher responsivity of the former results mainly from its smaller capture probability, pc, than that of the latter. Both transport as well as L valley occupancy appear important in determining the pc.