Influence of Quantum Well Width on Electron Transport and Resonant Characteristics in Double-Barrier Tunneling Diodes

Abstract

This study investigates the influence of quantum well width on electron transport and resonant characteristics in GaAs/AlGaAs double-barrier resonant tunneling diodes (DBRTDs) using a one-dimensional numerical model. The device is described within the effective-mass approximation, and electron transport is treated as coherent and ballistic. The practical component is entirely simulation-based and combines finite-difference eigenvalue calculations for the confined states with a transfer-matrix approach for energy-resolved transmission, followed by a Landauer-type formulation for the current–voltage characteristics. The quantum well width  is swept over a range of realistic values, while barrier height and thickness are kept fixed. The results show that the lowest resonant level and the associated resonance bias follow an approximate inverse-square dependence on , with finite-barrier and contact effects introducing a small offset. Even sub-nanometer variations in  are found to shift the resonant bias by tens of millivolts and to modify both peak current and peak-to-valley ratio. Narrow wells push the resonance to higher bias and increase sensitivity to structural variations, whereas wider wells lower the operating voltage and may introduce additional resonant levels within the same bias window. On this basis, an intermediate range of well widths is identified that offers a compromise between low operating voltage, acceptable peak current, and robustness to fabrication tolerances. The work highlights quantum well width as a primary design parameter and provides a simplified but physically meaningful framework to guide RTD optimization prior to more computationally intensive self-consistent or experimental studies.