Fig. 1. (a) The PBn structure, GaSb(P)/AlAsSb(B)/InAsSb(n); (b) the FTIR spectrum reveals that the cutoff wavelength of the InAsSb film is 4.5 μm at 300 K

Fig. 2. (a) Nomarski microscope image under 200-times magnification; (b) the HRTEM (High-Resolution Transmission Electron Microscope) cross-section result of the XBn InAsSb sample; (c) the HRXRD (High-Resolution X-ray Diffraction) result for the XBn InAsSb sample reveals that the full width at half maximum (FWHM) of InAsSb is 27 arcsecs; (d) the Atomic Force Microscope (AFM) results for the InAsSb sample indicate a root mean square (RMS) roughness of 0.19 nm

Fig. 3. (a)-(c) The dark current (J_dark) behavior under various temperatures and applied biases for samples A, B, and C, notably, at a temperature of 150 K and a bias voltage of -0.5 V, the dark current is measured approximately 1×10^-5 A/cm² for both sample A and B, whereas it decreases to 5×10^-6 A/cm² for sample C

Fig. 4. (a)-(f) The E_a variations under different temperatures and applied biases for samples A, B, and C, notably, at 250 K (depicted by the solid blue circle), E_a is measured approximately 300 meV, indicating the dominance of diffusion current in the dark current. Comparatively, E_a for samples A and B is smaller than that of Sample C, signifying the onset of the SRH process affecting device performance in the BL-doped samples, at a lower temperature of 150 K, the activation energy is approximately 200 meV, accompanied by an increased proportion of G-R current within the dark current

Fig. 5. (a) The Arrhenius fitting results for sample C, demonstrating the prevalence of diffusion current under low reverse bias voltage (-0.2 V), the Rule 07 reference for dark current is represented by the purple dashed line; (b) the photocurrent characteristics of the three samples are illustrated under various applied biases at 77 K, notably, the 'second-plateau' turn-on voltage is evident in samples A and B, the photocurrent IV for Sample C (represented by the blue solid line) is effectively fitted by the back-to-back diode model (as indicated by the purple dashed line); (c) the energy band profiles for the three samples at -0.4 V, as calculated by Silvaco