IMPROVEMENT OF INFRARED DETECTOR PERFORMANCE IN CARRIER DEPLETED STRAINED-LAYER TYPE-II SUPERLATTICES

The combined effects of suppressing Auger recombination in strained la yer superlattices (SL), photon recycling, and the suppression of both Auger and radiative recombination with carrier depletion are calculate d quantitatively for a 11 mu m 35.9 Angstrom InAs/15.7 Angstrom In0.22 5Ga0.775Sb and a 3.5 mu m 16.7 Angstrom InAs/35 Angstrom In0.25Ga0.75S b SL operating at temperatures between 200 and 300 K. The results are compared to their HgCdTe counterparts. The SL performance is better in all cases. However, the carrier concentrations required for backgroun d limited performance (300 K, 2 pi field of view), ranging between abo ut 1 x 10(13) and 4 x 10(13) cm(-3) at 300 K in both SLs, are seen to be impractically low. The carrier concentration in a 11 mu m photon de tector yielding equivalent performance to a 300 K thermal detector is about 10(14) cm(-3) Large performance enhancement using carrier deplet ion therefore appears impractical even in optimized SLs. (C) 1997 Amer ican Institute of Physics.