Properties of Above-Barrier Electronic States in Multi-Barrier structures

In the present work we report the detailed study of the above-barrier electronic states in the multi-barher structures by using the transfer matrix technique. The energy levels and the corresponding wavefunctions are calculated by solving the Schrodinger equation directly. Andy tical analysis is presented confirming the formation of sub band structure, similar to that determined by Kronig-Penney model. Each subband contains N energy states with N being the number of periods in the structure. Furthermore, our calculations demonstrate that in each subband there is one energy state whose wavefunction is always localized in the barrier regions, while others remain partly localized in general. These localized states satisfy the constructive condition k_bb = nπ in consistence with experiments, where kb is the wave vector in the barrier region, b is the barrier width, and n is an integer.