InSbNBi/InSb heterostructures for long wavelength infrared photodetector applications: A 16 band k · p study

Abstract

The intriguing potential of III-V-N-Bi materials like InSbNBi can lead to pervasive research curiosity in the long wavelength infrared (LWIR) regime. In this article, we have explored numerous prospective possibilities of utilizing InSbNBi for optoelectronic applications using a 16 band k · p Hamiltonian. Considering the lattice-matched condition of InSbNBi with host InSb, we have anticipated the bandgap, spin–orbit coupling splitting energy (ΔSO) and the corresponding operating wavelength of InSb0.9772N0.0028Bi0.02 as 68 meV, 0.824 eV, and around ∼18.23 μm, respectively. At room temperature, a wide range of selective bandgaps and related wavelengths ranging from 160 meV (∼8 μm) to 40 meV (∼30 μm) were obtained for Bi and N concentrations up to 2.5% and 0.35%, respectively. Co-incorporation of N and Bi results in ∼1.5 times reduction in the electron effective mass (0.0091 m0) compared to the host (0.014 m0), which further improves the optical gain of the InSbNBi/InSb quantum well system. The effect of both types of strain (compressive and tensile) on the InSbNBi/InSb system generated due to the deviation from the lattice matched ratio (0.14) of N and Bi offers interesting results. Along with a red shift in optical spectra, compressive strain (∼0.1%) offers a reduction in bandgap, electron effective mass, and enhancement in ΔSO by 44.7 meV, 0.0024 m0, and 12 meV, respectively. On the contrary, tensile strain (∼1.14%) increases the bandgap and the electron effective mass by 26.7 meV and 0.0066 m0, respectively, and reduces ΔSO by 219 meV. Nevertheless, tensile strain beyond 0.25% for a N concentration of 1.3% and fixed Bi concentration (1%) convert the InSbNBi/InSb heterostructure from a type I structure to a type II broken gap structure, which enables the possibility of realizing InSbNBi/InSb material for tunnel junction devices and the intermediate band solar cell along with the LWIR detector.