## 1 _Introduction_  
The detector is the heart of an infrared detection system. The third-generation infrared photodetector SWaP\({}^{3}\) (Size, Weight, Power, Performance and Price) concept is centered on improving performance with a smaller size, lower weight, lower power consumption, and cheaper cost [1]. For detectors in different spectral ranges, their own temperature affects them differently. The mainstream cooled LWIR (8-12 \(\upmu\)m) detectors of SWaP\({}^{3}\) are HgCdTe (cadmium mercury telluride), QWIP, and T2 SL (type ii superlattice) [2; 3; 4]. These types all require liquid nitrogen and need to be below the target cooling temperature to achieve good sensitivity in engineering applications. The body temperature of infrared cameras for satellite-borne Earth observation is close to the temperature of the detection target, and the detection effect is drastically affected by its own thermal radiation [5]. When working in orbit for a long time, the load's hood, external mechanism materials, and surface coatings show different degrees of degradation, which can cause the cooler to work in a poorer thermal environment [6; 7]. Whether it is the geostationary satellite FY-4 or the sun-synchronous orbit satellites HJ-2 and the Gaofen-4 satellite, there are fluctuations of about ten degrees outside the detector cooler [8; 9; 10; 11]. Factors such as the thermal environment and the performance of the cooler itself generate irregular fluctuations in the focal-planetemperature, and the dark current and its voltage signal obtained through integration vary with temperature, while bringing low-frequency time noise [8]. The QWIP has been widely used in recent years in LWIR detection systems, such as QWEST, Landsat 8 TRIS 1, and Landsat 9 TRIS 2 [12; 13; 14]. The materials typically used in QWIP devices are GaAs/AlGaAs [2]. The detector works as follows: the constituent materials form electron and hole potential wells in the energy band structure; photons from various sources cause the material to also produce electron and hole jumps for interband jumps in the sub-band; and an electric field is introduced externally to produce carriers, which are obtained through the electrodes and converted into a photocurrent. QWIPs have the following advantages: the GaAs substrate process is mature and has good lattice matching, which can support the preparation of large-area quantum well materials, while also having good uniformity, solid pixel material, and strong radiation resistance; it is also easy to change the device response band. Covering a wide spectral range, the system-related technology can be extended to other bands of detection; materials are easy to splice, with a high yield rate. For engineering applications, the target cooling temperature is typically 40-50 K for QWIP and around 77 K for HgCdTe. The dark current of QWIP is lower than that of HgCdTe at the respective typical cooling temperatures. The production difficulty of large-array HgCdTe detectors is high, and a QWIP is more likely to be the device of choice for projects with large-detector-volume requirements. At the same time, QWIPs have the disadvantage that the quantum efficiency at suitable operating points is one order of magnitude lower than that of HgCdTe [15]. The target cooling temperature is low, generally below the temperature of liquid nitrogen; additionally, according to [PERSON]'s law, the larger the temperature difference between the inside and outside of the dewar, the higher the heat flux, which challenges the temperature control level of the detector assembly, where very small temperature fluctuations may lead to changes in the focal-plane dark current. The dark current in a quantum well structure is mainly composed of free electrons drifting above the potential barrier and electrons captured by and emitted from the quantum well [15]. [PERSON], [PERSON], and [PERSON] systematically investigated the dark current mechanism in a QWIP and developed an analytical model [15; 16; 17].