Universal rule of revealing energy-band diagrams at various semiconductor interfaces: The influence of film thickness and dielectric constants

Abstract

Obtaining detailed energy-band diagram is always critically important at various semiconductor interfaces due to its direct instruction for optimizing and improving the performance of (opto-)electronic devices, which, therefore, always has been paid attention to by scientists. Despite the technological relevance of depicting energy-band diagrams at different types of semiconductors (inorganic, organic, and hybridized scenarios), the discrepancy at these interfaces still exists, and a reliable model that could potentially unify the full range of phenomena observed from these interfaces is still lacking. Here, we develop a theoretical framework to fill in this gap so that it could be capable of reproducing various band alignments at different semiconductor interfaces both qualitatively and quantitatively. Our model could further allow us to resolve some conflicting views in the literature related to the influence of substrate work functions, which should be considered differently between inorganic and organic semiconductor interfaces. Our results also highlight the importance of dielectric constant differences and the film thickness as critical factors in driving charge transfer at semiconductor interfaces through integrating different density of states with Fermi–Dirac distribution functions in various semiconductors, which hopefully could promote the numerical study on developing functional semiconductor devices.