Role of fluctuations in carrier transfer in semiconductor heterostructures

Influence of the electrical potential fluctuations on quantum transfer effects in semiconductor heterostructures is analyzed. It is shown that, contrary to the bulk 3D case, carriers capture by a quantum well or tunneling through a potential barrier is not characterized by optimal fluctuation. Spin-dependent tunneling in single-barrier nonmagnetic structures is shown to be insensitive to the fluctuations while in double-barrier structures fluctuations substantially reduce achievable spin polarization of the carriers. It is demonstrated that while for realistic AlGaAs heterostructures carriers capture by a quantum well keeps its resonance behavior, for presently actual InGaN-based heterostructures the capture probability becomes a smooth function of the quantum well parameters.