Modeling of MoS2/Si heterostructure to study charge transfer dynamics

Abstract

Here, we synthesized a MoS _2 /Si heterojunction device using a scalable approach involving DC sputtering coupled with sulfurization. The observed current–voltage characteristics unequivocally indicate a rectifying behavior at MoS _2 /Si heterointerface. To quantitatively assess the carrier dynamics, a comprehensive analysis utilizing thermionic emission and Landauer transport formalism model was employed. The spatial variation in current across the MoS _2 /Si devices suggests a potential influence of MoS _2 ’s in-plane series resistance. Furthermore, the electrical behavior of the device is found to be temperature-dependent, with higher temperatures resulting in enhanced conductivity attributed to an increase in thermally generated charge carriers. As temperature rises, the Landauer current model observes an increased ratio of density of states to carrier injection rate, along with other temperature-dependent terms. Meanwhile, the thermionic current model maintains a fixed effective value for its material-dependent term, the Richardson constant, irrespective of temperature changes. Therefore, a comparative analysis between thermionic emission and Landauer transport formalism reveals that the conventional thermionic emission model better aligns with experimentally observed leakage current in reverse bias, showcasing a minimal barrier height at the heterojunction. This comprehensive investigation provides valuable insights into the charge transfer mechanisms at the MoS _2 /Si interface, opening avenues for its potential innovative applications in electronic devices.

Keywords

• heterostructure
• barrier height
• ideality factor
• thermionic emission
• Landauer transport