Exploring the optoelectronic properties of medium-wave dual-color detectors based on asymmetric InAs/InAsSb superlattice niBin structure

Abstract

The short-mid-/mid-wave infrared (SMWIR/MWIR) detectors can capture target information in two bands simultaneously, enhancing the recognition accuracy in challenging interference scenarios by suppressing complex background. Here, we explore the optoelectrical properties of InAs/InAsSb-superlattice-based dual-band niBin detectors consisting of SMWIR/MWIR absorbers separated by an AlGaAsSb unipolar barrier. The experimental and simulated results show that: i) The bandgaps of both SMWIR and MWIR absorbers can be consistently determined via transmission and photocurrent spectra, giving cutoff wavelengths of ∼ 4.16 µm and ∼ 5.21 µm (77 K), respectively, well in line with the design values; ii) The device structure shows n-type conductivity by Hall measurements, based on which the conduction and scattering mechanisms at various temperatures can be clarified; iii) Dark current density analysis reveals the temperature dependent dominant current mechanisms, i.e., the generation-recombination current in 150 K − 210 K and the diffusion current above 210 K; and iv) The Burstein-Moss effect can make the determined optical bandgap slightly redshifted (∼34 meV), as compared to that of electrical techniques. This work provides new insights into bandgap engineering and structural design for MWIR dual-color detectors based on InAs/InAsSb superlattices.