Boundary conditions in characterizing InxGa1−xAs /GaAs quantum well infrared photodetector

We study the optical transition between bound-to-continuum states in InGaAs/GaAs quantum well infrared photodetector (QWIP) by analyzing two possible boundary conditions for the continuum states. InGaAs/GaAs QWIP differs from the GaAs/AlGaAs QWIP in many aspects. Comparing running wave function and Bloch wave function with experimental results, we find that Bloch wave function is the much more suitable boundary condition for multiple InGaAs/GaAs quantum well (QW) structure. The blueshift of the responding peak is smaller when the Bloch wave boundary conditions apply.