Normal-incidence quantum-well infrared photodetectors utilizing ellipsoidal valley intersubband transitions in n-type GaSb-AlSb multiquantum wells

摘要

We report on the observation of normal incidence IR photoconductive detector response in ellipsoidal valley n-type GaSb-AlSb multi-quantum well samples, grown on (001) GaAs substrates by molecular beam epitaxy. Photoconductors were fabricated and IR detector response was measured using Fourier transform IR spectroscopy. Detector response was observed in the long wavelength IR band at $lambda $EQ 8.5 $mu@m for an operating temperature of T $EQ 77 K, and agrees well with absorption data. We also show preliminary results on a method for extending the intersubband transition energies to longer wavelength.