Study of intersubband transition in quantum dots and quantum dot infrared photodetectors

In this paper the intersubband optical transitions in quantum dots are studied. Theoretical calculations of peak wavelengths and oscillator strengths of the transitions from the bound to first and second excited states were made for the InxGa1-xAs/GaAs and InAs/AlxGa1-xAs systems. The results show that transition from the ground to the first excited state in the growth-direction polarization has the largest absorption. The results of our calculations were found to be in good agreement with the observed peak detection wavelengths of the quantum dot infrared photodetectors (QDIPs). The application of quantum dots structures for the mid- and long-wavelength infrared detection is also discussed. (C) 1999 Elsevier Science B.V. All rights reserved.