High-responsivity GaInAs/InP quantum well infrared photodetectors grown by low-pressure metalorganic chemical vapor deposition

摘要

Abstract: We have studied the dependence of the well doping density in n-type GaInAs/InP quantum well IR photodetectors (QWIPs) grown by low-pressure metalorganic chemical vapor deposition. Three identical GaInAs/InP QWIP structures were grown with well sheet carrier densities of 1 by 10$+11$/ cm$+$MIN@2$/, 3 by 10$+11$/ cm$+$MIN@2$/, and 10 by 10$+11$/ cm$+$MIN@2$/; all three samples had very sharp spectral response at $lambda $EQ 9.0 $mu@m. We find that there is a large sensitivity of responsivity, dark current, noise current, and detectivity with the well doping density. Measurements revealed that the lowest-doped samples had an extremely low responsivity relative to the doping concentration while the highest-doped sample had an excessively high dark current relative to doping. The middle-doped sample yielded the optimal results. This QWIP had a responsivity of 33.2 A/W and operated with a detectivity of 3.5 by 10$+10$/ cmHz$+1/2$/W$+$MIN@1$/ at a bias of 0.75 V and temperature of 80 K. This responsivity is the highest value reported for any QWIP in the $lambda $EQ 8-9 $mu@m range. Analysis is also presented explaining the dependence of the measured QWIP parameters to well doping density. !10