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In the present paper it is demonstrated that the bound electronic states of multiple quantum wells structures may be calculated very efficiently by expanding their eigenstates in terms of the eigenfunctions of a particle in a box. The bound states of single and multiple symmetric or nonsymmetric wells are calculated within the single-band effective mass approximation. A comparison is then made between the results obtained for simple cases with exact calculations. We also apply our approach to a GaAs/AlGaAs multiple quantum well structure composed of forty periods each one with seven quantum wells. The method may be very useful to design narrow band quantum cascade photodetectors to work without applied bias in a photovoltaic mode. With the presented method the effects of a electric field may also be easily included which is very important if one desires study quantum well structures for application to the development of quantum cascade lasers. The advantages of the method are also presented.

AlGaAsSb/AlAsSb Bragg mirrors lattice matched on InP with six pairs of layers were grown by molecular beam epitaxy. The effect of Te doping on the electrical and optical properties of the Bragg mirrors, and the presence of digital alloy gradient layers between the ternary and quaternary layers are analysed. The presence of digital alloy layers at the interfaces reduces the electrical resistance through the perpendicular direction of the Bragg mirror, without significantly affecting the reflectivity.

The temperature dependence of excitonic transitions in double quantum well heterostructures in the temperature range of 2–300 K were investigated. A crossing between excitonic transition experimental curves as a function of temperature in quantum wells of the same thickness and different barrier height is observed. The influence of the barrier height on the temperature dependence of excitonic states in the quantum wells is analyzed.

We report electrical and optical characteristics of a Si-doped (Al)GaInAs digital alloy/AlInAs Bragg mirror lattice matched to InP grown by molecular beam epitaxy. A 98.2% reflectivity with a 107 nm stop band width centred at 1.54 μ m is obtained. An average voltage drop of 16 mV per period at a current density of 1 KA cm − 2 is observed for a mean electron concentration of about 5.5 × 10 18 cm − 3 . The influence of structural and intrinsic properties of the heterostructure on the electrical resistivity and optical reflectivity is analysed.