This　paper　studies　superlattice　materials　with　M　barrier　(InAs/GaSb/AlSb/GaSb　superlattice)　and　B　barrier　(InAs/AlSb　superlattice)　structures.　Firstly,　it　introduces　the　diffusion　current,　generation-recombination　current,　tunneling　current　and　surface　leakage　current　in　devices,　and　analyzes　the　factors　affecting　different　dark　current　mechanisms.　Secondly,　it　theoretically　analyzes　the　influence　of　the　two　barrier　structures　on　device　performance.　Finally,　devices　were　fabricated　using　these　two　structures,　and　the　device　performance　was　characterized.　At　a　bias　voltage　of　-50　mV　and　operating　temperature　of　77K.　The　PIMN　type　long-wave　infrared　(LWIR)　detector　has　an　RA　of　91.4　omega　cm2　and　a　LW　dark　current　density　of　3.51　x　10-4　A　cm-2.　The　PIBN　type　LWIR　detector　has　an　RA　of　439　omega　cm2　and　a　LW　dark　current　density　of　2.81　x　10-4　A　cm-2.　Meanwhile,　by　fitting　the　data　at　different　temperatures,　the　activation　energy　Ea　of　the　PIMN　type　LWIR　detector　is　119.8　meV,　with　dark　current　mainly　determined　by　diffusion　current　and　generation-recombination　current.　The　activation　energy　Ea　of　the　PIBN　type　LWIR　detector　is　126.2　meV,　with　dark　current　mainly　determined　by　diffusion　current.　This　experimentally　verifies　the　dominant　dark　current　mechanisms　for　the　two　barrier　structures　of　LWIR　detectors,　providing　strong　support　for　the　design　of　superlattice　detector　structures.