## 3 Results  
Electrical testing was performed at different temperatures for all the SLS samples. The results showed that implantation energy and dose were the most critical parameters for the electrical performance analysis. The results showed that increasing the implantation energy can cause a drop in dark current for both \(nBn\) and \(pBn\) planar diodes. However, introducing high energy ions to the SLS structure can impose a great risk of damage-related increase in the dark current, such as hopping conduction effect [23; 24]. Thus, the unlimited increase of dose or energy of implantation is not recommended and had to be optimized. Given that the implantation technique was used for diode formation, at higher implantation energies, each incident ion can reach deeper and cause more damage to the SLS structure, which in turn causes more isolation. Raising the dose can also provide similar impacts during implantation and creates effective isolation between adjacent diodes [23]. The best case is to optimize the dose and energy at the same time to achieve the most effective implantation approach. It was found that the implantation energy of 300 KeV for the \(nBn\) design and 380 KeV for the \(pBn\) design showed the lowest dark current values for each chosen implantation doses. Figure 3a,b demonstrates a comparison of the dark current density versus the temperature of planar SLS diodes implanted with different implantation doses for \(pBn\) at \(-\)40 mV applied bias (V\({}_{\text{b}}\)) (380 KeV implantation energy) (a) and \(nBn\) (V\({}_{\text{b}}\) = \(-\)80 mV, 300 KeV implantation energy). The result led to the conclusion that the highest dose of 1 \(\times\) 10\({}^{15}\) cm\({}^{-2}\) is the choice for the optimized condition for each case. Table 1 summarizes the optimized case of implantation for each device. Using the SRIM simulation for these optimized conditions, the estimated values for the depth of ion concentration peak and straggling inside the SLS material are given in Table 1 as well. Figure 3: (**a**) Dark current values versus temperature for the planar MWIR SLS diodes: (**a**) \(pBn\) (V\({}_{\text{b}}\) = \(-\)40 mV, 380 KeV implantation dose) and (**b**) \(nBn\) (V\({}_{\text{b}}\) = \(-\)80 mV, 300 KeV implantation dose) fabricated with different implantation doses. All diodes were circular with a 200-μm diameter. Figure 3 also presents an interesting comparison of the dark current density values for both the \(pBn\) and \(nBn\) planar and mesa-isolated devices. The results show that the dark current values for mesa-isolated SLS diodes were still lower compared to the planar diodes. This issue will be addressed shortly. The dark current density values versus bias voltage at 77 K and 150 K for both optimized implantation conditions for the MWIR \(nBn\) and \(pBn\) planar devices are shown in Figure 4a,b, respectively. All the diodes had a 200-\(\upmu\)m diameter circle shape. For the \(nBn\) device, the dark current density values at \(\rm V_{b}=-80\) mV at 77 K and 150 K were \(1.23\times 10^{-6}\) A/cm\({}^{2}\) and \(1.42\times 10^{-4}\) A/cm\({}^{2}\), respectively (Figure 4a). For the \(pBn\) device at the bias voltage of \(-40\) mV, the dark current density values at 77 K and 150 K were \(5.21\times 10^{-6}\) A/cm\({}^{2}\) and \(2.68\times 10^{-3}\) A/cm\({}^{2}\), respectively (Figure 4b). In the inset of Figure 4, the dark current values for the optimized planar SLS photodetectors were compared with traditional mesa-isolated devices for the same size of diodes. As it can be seen, at the low range of temperature \(<\) 100 K, the values for the planar devices were in the range of 2-3 (for \(nBn\)) and 6-8 (for \(pBn\)) times higher compared to the mesa-isolated devices. The dark current performance was overall better for the planar \(nBn\) device compared to its \(pBn\) counterpart. The gap between the dark current value for planar and mesa-isolated SLS diodes was much worse at higher temperatures.