Theoretical utmost performance of (100) mid-wave HgCdTe photodetectors

Abstract

HgCdTe detectors designed to detect mid-wavelength (3-5 lm) infrared radiation must be cooled to reach the required performance. The cooling requirement makes the sensor system both expensive and bulky and the fundamental goal is to reach higher operating temperature condition preserving near background limited performance with high detectivity and high speed response at the same time. In order to reach higher operating temperature condition the thermal generation rate must to be suppressed under the photon generation rate. Except Auger 7 generation-recombination process, p-type HgCdTe is mostly limited by technology dependent Shockley-Read-Hall generationrecombination mechanism. One of the ways to reduce the trap density is a growth of the (100) HgCdTe on GaAs substrates. That orientation allows reaching lower carrier concentration *5 9 10 14 cm -3 in comparison to the commonly used (111) orientation *5 9 10 15 cm -3 in mid-wavelength infrared range. In addition, it was presented that Shockley-Read-Hall traps density could be reduced to the level of *4.4 9 10 8 cm -3 . The theoretical simulations related to the utmost performance of the (100) HgCdTe Auger suppressed structures are presented. Dark current is reported to be reduced by more than one order of magnitude within the range *6 9 10 -2 -3 9 10 -3 A/cm 2 . Detectivity increases within range *3-12 9 10 11 cm Hz 1/2 /W (wavelength *5 lm) at temperature 200 K and voltage 200 mV.

Ultrasensitive Mid-wavelength Infrared Photodetection Based on a Single InAs Nanowire

“…Meanwhile, with such a high ferroelectric polarization field, the defect states onto the NW surfaces can be preadjusted and filled with electrons to completely shield the ionization scattering, resulting in a large increase in carrier mobility and lifetime in the NW core. These greatly increase the detection sensitivity of our InAs NW photodetector: not only the D * is greater than that current reported and commercial devices but also R is ∼4 orders higher than that reported at λ = 3.5 μm. − ,− ,,,− In addition, the strong band bending and the Franz–Keldysh effect caused by such a high polarization field further enable sensitive sub-band gap photodetection through InAs NWs, extending the detector’s photoresponse beyond the InAs band gap and exhibiting high performance.…”

“…On the other hand, the photodetectors in photoconductive or photovoltaic mode may offer an option to realize high response and signal-to-noise ratio infrared detection without the influence of increased noise. InSb and HgCdTe (MCT), by far the paradigmatic candidates for MWIR applications, demonstrate strong performance and have been widely used in commercial products with high detectivity ( D *) of ∼10 11 cm·Hz 1/2 W –1 and responsivity ( R ) of 3 A W –1 at 77 K. − Some emerging materials, such as bP/MoS 2 heterojunctions, HgTe CQDs/As 2 S 3 , and hBN/b-AsP/hBN heterostructures, also show a very attractive application prospect in MWIR detection. However, although these detectors exhibit good detectivity (about 10 11 cm·Hz 1/2 W –1 ), their R values are quite low (no more than 3 A W –1 ).…”