## 2 Material Growth Procedure  
Each T2 SL InAs/InAsSb structure was grown in a RIBER Compact 21-DZ solid source MBE system, on 2\" semi-insulating GaA (001) substrates. The substrate temperature during the growth was monitored by a manipulator thermocouple. The substrate temperature was the only parameter being changed intentionally during the growth campaigns. A detailed description of the buffer layer growth and substrate preparation procedure can be found elsewhere [9]. The T2 SLs growth conditions and parameters were adapted after [PERSON] et al. and [PERSON] et al. [10; 11]. The GaA substrates were used to implement low-cost substrates in the mass fabrication of the backside-illuminated devices. Two sets of samples were prepared. The T2 SL growth parameters are presented in Table 1. The approx. 300 periods (\(P\)) T2 SLs InAs/InAsSb were grown on 250 nm GaAs smoothing layer, followed by 1.2 \(\upmu\)m thick GaSb buffer on the GaAs substrates. The 1.2 \(\upmu\)m thick buffer connected with interfacial misfit array (IMF) growth mode allowed high-quality structures to be obtained without any surface corrugations for the IR photoconductor's final fabrication [12; 13; 14]. Sets I and II differ in the superlattice period and include samples with and without beryllium (Be) doping marked, respectively (superscripts: \"+\"; \"\(-\)\"), as shown in Table 1. The Be doping was used to increase the final device sheet resistance, and it is not a focus of this research. The Be doping is used to reach the HOT condition for the LWIR detectors--that is why Be-p-type doping was implemented. Auger generation recombination rates are strongly dependent on temperature via the dependence of carrier concentration and intrinsic times on temperature. Therefore, cooling is one of the effective ways to suppress Auger processes. Since intrinsic \(\tau_{\Delta\gamma}\) is larger than intrinsic \(\tau_{\Delta\gamma}\), Auger processes can be minimized also by optimized p-type doping. An optimized p-type significantly improves the performance, compared with that of an undoped material, but excessive doping lowers the device's performance [15]. Figure 1: Interfaces in (**a**) InAs/GaSb SL and (**b**) InAs/InAsSb SL. High-resolution X-ray diffraction (PANalytical X'Pert--HRXRD) was utilized to assess the structural properties of the T2 SLs InAs/InAsSb. The MBE growth temperature is presented as a variation from a nominal value \(\sim\)425 \({}^{\circ}\)C. This is motivated by the general problem of the temperature representation in the MBE chamber. There are three dominant methods of temperature measurements: pyrometer, thermocouple of the manipulator (used here), or the _BadniT_ system. Each method exhibits its own limitation, and the combination of at least two was used in the early stage for the growth condition optimization. The value \(\sim\)425 \({}^{\circ}\)C represents optimal growth parameters in our MBE chamber, which included the type of manipulator, substrate, and molybdenum block thicknesses or molecular beams. Figure 2 presents the HRXRD spectra for the samples given in Table 1. The full-width at half-maximum (FWHM) values of the 0 th/GaSb-order HRXRD peaks of the analyzed T2 SL samples should be considered indicators of the grown T2 SLs material quality and are presented in Table 1.  
The samples were optimized in terms of the material used during the MBE growth procedure and lattice-matched condition to GaSb buffer, which was confirmed by \(\Delta a\)/\(a\) GaAs-0 th/GaSb, assuming 7.274% (average) for Set I and 7.273% for Set II samples, respectively. For Set I samples, the material quality improved as the substrate temperature decreased from 450 \({}^{\circ}\)C to 400 \({}^{\circ}\)C, and the lowest FWHMs were observed for the samples grown at 400 \({}^{\circ}\)C. For SET II, this behavior was not observed, and the highest FWHM corresponded to the longest \(\lambda_{50\%\textit{cut-off}}\) (18 \(\upmu\)m and 16 \(\upmu\)m) and highest values of \(\Delta a\)/\(a\) GaAs-0 th/GaSb (7.312% and 7.278%).