Effect of remote band coupling on net recombination current in type-II heterostructures

Abstract

Exact analytical expressions for the eigenvalues and eigenvectors of the six-band k·p matrix Hamiltonian for narrow-gap III-V semiconductors are used to derive an analytical expression for the transmission coefficient T in type-II heterojunctions. The remote band coupling is included via the two Luttinger-type parameters, γ1 and γ̃. The expression for T contains two separate contributions: one from electron to light-hole tunneling and the other from electron to heavy-hole tunneling. Using the expression for T, the net recombination current density J is defined and evaluated for the specific case of an InAs/GaSb heterojunction. Ohmic behavior is observed in J for small applied voltages V approximately in the range -0.15 to 0.075eV. Outside of this range, J changes nonlinearly with respect to changes in V. Comparison of the heavy-hole and light-hole contributions to J shows that the heavy-hole contribution increases J by approximately 10% at room temperature. The results for the InAs/GaSb heterojunction are in qualitative agreement with recent experimental observations. © World Scientific Publishing Company.