Detection wavelength of InGaAs/AlGaAs quantum wells and superlattices

InGaAs/AlGaAs quantum well structures have been shown to be versatile for infrared detection. By changing the material composition, one can tune the detection wavelength from 2 to 35 mum and beyond. However, there have been few systematic calculations on the absorption wavelength of these structures with respect to their structural parameters. In this work we have adopted the transfer-matrix method to calculate both their energy levels and the wave functions. From this calculation, the absorption and the responsivity spectra of the structures can be predicted. The theory agrees with the experimental result of the test structures. Supported by the experimental evidence, we applied the calculation to a general class of midwavelength detectors and thus established a useful guideline for the detector design in this wavelength range. (C) 2002 American Institute of Physics.