I-V characteristics of resonant tunneling devices: Difference equation method

We have developed a full-band-structure-based theory to calculate the transmission coefficients through nanostructures of semiconductor quantum wells and barriers. This method, based on the solution to a difference equation, is efficient, numerically stable, and accurate. The I-V characteristics of realistic resonant tunneling diodes are calculated, and this method enables us to follow the contribution to the spatially resolved current from channels mediated by different valleys. We have carried out a systematic study of I-V characteristics in GaAs/AlAs double-barrier resonant structures using a second-neighbor tight-binding Hamiltonian. Our calculations clearly show that the energy separation between the quantized Γ state in GaAs and X state in AlAs plays a crucial role in determining the peak-to-valley current ratio. We further show that the quantized states and peak-to-valley current ratio are sensitively dependent on the tight-binding parameters. © 1998 American Institute of Physics.