Theoretical Study of the Effect of Stresses on Effective Masses in the InAs/InAsSb Type-II Superlattice ^†

Abstract

A³B⁵ materials used in the construction of a superlattice have properties that enable the design of devices (to include avalanche photodiodes) optimized for use in infrared detection. These devices are used in the military and medicine industries, and in other areas of science and technology. This paper presents a theoretical assessment and analysis of the impact of stresses on an InAs/InAsSb type-II superlattice (T2SL) grown on a GaSb buffer layer, considering band gap energy and effective masses at a temperature of 150 K. The theoretical research was carried out with the use of the commercial platform “SimuApsys” (Crosslight). The method kp 8·8 (k = 0.06) was adopted in T2SL modeling. Luttinger coefficients (γ₁, γ₂ and γ₃) were assessed assuming the Kane coefficient F = 0. The band gap energy of InAsSb ternary materials was determined assuming that the bowing parameter for the above-mentioned temperature was b_g = 0.75 eV. The cut-off wavelength values were estimated on the basis of theoretically determined absorption coefficients (α). The energy gap was calculated according to the following formula: E_g = 1.24/λ_cut-off. From the analysis of theoretical results, it can be concluded that the stresses in T2SL cause the E_g shift, which also has an impact on the influence on the change of the effective masses m_e and m_h, which play an important role in the optical and electrical parameters of the detection structure. The simulated theoretical parameters T2SL at 150 K are comparable to those measured experimentally.