Room-temperature InAsSb photovoltaic detectors for mid-infrared applications

Novel noncryogenic InAsSb photovoltaic detectors grown by molecular beam epitaxy are proposed and demonstrated. The quaternary alloy In
_0.88
Al
_0.12
As
_0.80
Sb
_0.20
is introduced as a wide bandgap barrier layer lattice matched to the GaSb substrate. The valence band edge of In
_0.88
Al
_0.12
As
_0.80
Sb
_0.20
nearly matches with InAs
_0.91
Sb
_0.09
, leading to more efficient transport of photogenerated holes. The resulting mid-infrared photovoltaic detector exhibits a 50% cutoff wavelength of 4.31 mum and a peak responsivity of 0.84 A/W at room temperature. High Johnson-noise-limited detectivity (D
^*
) of 2.6times10
⁹
cmmiddotHz
^1/2
/W at 4.0 mum, and 4.2times10
¹⁰
cmmiddotHz
^1/2
/W at 3.7 mum are achieved at 300 K and 230 K, respectively