Current transport modeling in quantum-barrier-enhanced heterodimensional contacts

A physical model for electron and hole current transport is formulated in a novel heterodimensional contact that incorporates a barrier-enhancement region between a two-dimensional optically active InGaAs/InAlAs quantum well and a three-dimensional metal contact. Developed for easy inclusion in fully self-consistent numerical device simulators, these quantum-mechanical-transmission boundary conditions are useful to investigate important carrier transport effects such as carrier accumulation and thermionic and tunneling emission in heterodimensional contacts, dc current simulations of the quantum-barrier-enhanced structure are compared with simulated currents in a structure with direct metal contact to the InGaAs quantum well. Results indicate a reduction in dark current of nearly three orders of magnitude, making these contact structures attractive for low-noise photodetector applications. Additionally, simulation of the transient current response of a photodetector with 1-μm interdigitated contact spacing indicates an electrical bandwidth of 50 GHz.