HIGH-PERFORMANCE INAS GA1-XINXSB SUPERLATTICE INFRARED PHOTODIODES/

The optical and electrical properties of infrared photodiodes diodes b ased on InAs/(GaIn)Sb superlattices grown by molecular beam epitaxy we re investigated. The diodes, with a cut-off wavelength around 8 mu m s how a current responsivity of 2 A/W. By proper adjustment of the p-dop ing level above the n-background concentration the depletion width exc eeds a critical size of about 60 nm, leading to the suppression ol ban d-to-band tunneling currents. Above that critical width the dynamic im pedance R(0)A at 77 K reaches values above 1 k Omega cm(2) leading to a Johnson-noise-limited detectivity in excess of 1 x 10(12) cm root Hz /W. (C) 1997 American Institute of Physics.