Type-II InAs/GaSb photodiodes and focal plane arrays aimed at high operating temperatures

Abstract

Recent efforts to improve the performance of type II InAs/GaSb superlattice photodiodes and focal plane arrays (FPA) have been reviewed. The theoretical bandstructure models have been discussed first. A review of recent developments in growth and characterization techniques is given. The efforts to improve the performance of MWIR photodiodes and focal plane arrays (FPAs) have been reviewed and the latest results have been reported. It is shown that these improvements has resulted in background limited performance (BLIP) of single element photodiodes up to 180 K. FPA shows a constant noise equivalent temperature difference (NEDT) of 11 mK up to 120 K and it shows human body imaging up to 170 K.

Barrier infrared detectors

“…Absence of a depletion region offers a way for materials with relatively poor SR lifetimes, such as all III−V compounds, to overcome the disadvantage of large depletion dark currents. Its practical application has been demonstrated in InAs [4,7,16], InAsSb [8,10,13,17,18] InAs/GaSb T2SLs [5,9,14,15] and recently, also in HgCdTe ternary alloy [19,20]. The main requirement which must be met to construct the barrier detector structure is "zero" band offset in a pro− per band depending on carrier type which is to be blocked.…”

“…The pBp architecture should be employed when the surface conduc− tion of the materials is p−type and must be used a p−type absorbing layer. The last structure can be realized using, e.g., a p−type InAs/GaSb T2SLs as the absorbing layer [14,15]. So called pMp device consists of two p−doped super− lattice active region and a thin M−structure with higher energy barrier.…”

Comparison of the electro-optical performances of MWIR InAs/GaSb superlattice pin photodiode and FPA with asymmetrical designs

“…For the last past years, type-II InAs/GaSb superlattice (T2SL) seems to be a good candidate for high operating temperature (HOT) infrared detectors [1][2][3][4] in the mid-wavelength infrared (MWIR) domain. Most of the SL periods reported for the MWIR detection present an InAs to GaSb thickness ratio R close to 1 [2,5].…”

Study of interfaces chemistry in type-II GaSb/InAs superlattice structures

“…GaSb-based superlattices (SLs) are well recognized for obtaining high-performance modern microand optoelectronic devices including infrared detectors, long-wavelength lasers and high-frequency, low-voltage field effect transistors. In particular, the GaSb/InAs system is promising for the next generation mid-infrared photodetectors focal plane arrays as an alternative material to usually used HgCdTe alloy for better uniformity, reduced tunneling currents and suppressed Auger recombination [1][2][3]. For many of type-II GaSb/InAs superlattices applications the band alignment plays a critical role in the device performance, however, a determination of band alignments in mixed anion/cation systems is complicated by the fact that two different types of interfaces can be formed.…”