Type-II InAs/GaSb strain layer superlattice detectors for higher operating temperatures

Progress in Infrared Photodetectors Since 2000

“…While none of the devices are capable of room temperature operation, a handful were capable of operation between 200 and 240 K. The expansion of FPA size, and perhaps the inclusion of other features such as current blocking layers into these devices, led to a small decrease in NETD, usually in the 20–30 mK range. These figures may seem low, however they are still more than sufficient for the purposes of an FPA [161–164]. By the end of the decade, a megapixel FPA had been fabricated, and its responsivities and detectivities remained similar to those found in previous FPAs.…”

“…One of the highest performing single pixel devices is capable of a D * of 1 × 10 9 for a cutoff wavelength of 4.3 μm at room temperature. Barrier layers were investigated for both the conduction band (nBn structures) and the valence band (pBp structures), but nBn (Figure 7) were far more popular in the early stages of research [146,161,183–185]. A small FPA (320 × 256 pixels) was fabricated using nBn technology, having comparable performance to single pixel devices in the MWIR regime.…”

Performance analysis of an N-structure type-II superlattice photodetector for long wavelength infrared applications

“…To get higher working temperature, higher QE, lower dark current and higher specific detectivity, researchers proposed a lot of designs, such as nBn [7], pBiBn [8], CBIRD [9], W-structure [10], M-structure [11] and etc. These designs can effectively reduce the dark current.…”

Digital metamorphic alloys

“…For instance, the InAs/GaSb SL system has been used for mid-IR devices, 5 the GaN/ AlGaN material system as buffers in nitride-based devices, 6 the GaAsP material system as buffers for heterovalent integration of Si and III-Vs, 7,8 and the GaAs/Al͑Ga͒As and Si/ SiGe/Ge systems, among many others, for the construction of digital alloys. 9,10 In all these instances, however, the focus has generally been on unstrained or strain-compensated structures, where the SL structures are tailored to a specific substrate or lattice constant, and the constituent layers of the SLs are chosen such that the signs and magnitudes of their respective strains cancel out when averaged over the entire SL structure.…”