Intersubband infrared detector with optimized valence band quantum wells for 3-5 mu m wavelength region

We present results on a p-type intersubband infrared detector for the 3-5 m u m wavelength region with optimal quantum well design. For valence band qu antum wells made by the AlGaAs/GaAs heterosystem with negligible strain, th e ground state subband is the first heavy hole subband, and a structure wit h the second light hole subband in resonance with the top of the barrier is optimal for normal incidence. Using this resonance design, the fabricated detector shows good performance with a background limited operating tempera ture of 100 K. Our experiments also show a clear polarization dependence fo r different intersubband transitions involving heavy hole to heavy hole and heavy hole to light hole processes. [S0021-8979(99)07504-0].