Infrared application of quantum well structures

The invention and the investigation of the semiconductor quantum well structures have influenced and changed the condensed matter physics, microelectronics, opto-electronics as well as other related scientific and technological fields tremendously in last three decades. The quantum well, superlattice and their new development or new generation, that is quantum wires and quantum dots and many other microstructures provide us furthermore really new challenge for the infrared application and technology. The cascade infrared laser, the multi-color and tunable infrared detectors, as well as the focus plane array based on the intersubband or interband transitions in usual multi quantum well or type-Il superlattice structures are some of the examples. We report here mainly a comprehensive investigation on the application of GaAs/AlGaAs multi-quantum well structures as the long wavelength infrared detectors and their focus plane arrays based on the intersubband transitions of the quantum wells. The fundamental parameters of these;zes, the performance of the detectors and the arrays, the modulation and tuning of detection wavelength via atom intermixing between wells and barriers, the coupling of the radiation with the electronic transitions and the demonstration of the imaging will be reviewed and discussed together with the comparison to the traditional infrared detectors.