Tunnelling and current density in short period strained AlN/GaN superlattices

• We model strained AlN/GaN superlattice by means of transfer matrix formalism.
• We calculate the transmission coefficient and the tunnel current density.
• Broadening, destroying and regrouping of the minizones are observed.
• Oscillation behavior of the tunnel current is observed.
• Conductance calculations are in agreement with the experimental data.

In this paper we theoretically analyze the under-barrier perpendicular transport in short period strained III-nitride superlattices via a generalized model. The transmission coefficient of unbiased and biased structures, as well as the tunnel current at room temperature, are calculated via the transfer matrix formalism and the effective mass approximation. The inherent to the III-nitrides electric polarization fields taken into account and the exact solution of the Schrödinger equation is used in the calculation process. The minizone structure is shown to periodically disintegrate and reform as the externally applied electric field increases, while the tunnel current density shows nonlinear behavior and negative differential conductance. The theoretical results we obtain are compared and found to be consistent with the experimental ones.