InxGa1-xAs/AlyGa1-yAs/AlzGa1-zAs asymmetric step quantum-well middle wavelength infrared detectors

InxGa1-xAs/AlyGa1-yAs/AlzGa1-zAs asymmetric step quantum-well middle wavele ngth (3-5 mum) infrared detectors are fabricated. The components display ph otovoltaic-type photocurrent response as well as the bias-controlled modula tion of the peak wavelength of the main response, which is ascribed to the Stark shifts of the intersubband transitions from the local ground states t o the extended first excited states in the quantum wells, at the 3-5.3 mum infrared atmospheric transmission window. The blackbody detectivity (D-bb*) of the detectors reaches to about 1.0x10(10) cm Hz(1/2)/W at 77 K under bi as of +/-7 V. By expanding the electron wave function in terms of normalize d plane wave basis within the framework of the effective-mass envelope-func tion theory, the linear Stark effects of the intersubband transitions betwe en the ground and first excited states in the asymmetric step well are calc ulated. The obtained results agree well with the corresponding experimental measurements. (C) 2001 American Institute of Physics.