Determine the role of trap-assisted tunneling in M/Nb:STO resistive switching

Determine the role of trap-assisted tunneling in charge transport and resistive switching in metal/Nb-doped SrTiO3 Schottky junctions, and establish whether it contributes materially alongside thermionic emission and thermionic-field emission.

Background

The paper identifies trap-assisted tunneling as a possible transport pathway in metal/Nb:SrTiO3 junctions because oxygen vacancies and other defect states can provide intermediate states within or near the Schottky barrier. Several studies have proposed that tunneling paths, resonant tunneling, or a combination of charge trapping and tunneling may contribute to resistive switching.

However, trap-assisted tunneling is difficult to distinguish experimentally from thermionic emission and thermionic-field emission, and the paper notes that existing current-voltage scaling evidence is insufficient to establish its importance in M/Nb:SrTiO3. Resolving this issue would clarify whether resistance changes arise primarily from trap occupancy and Schottky-barrier modulation or from defect-mediated tunneling pathways.

References

Trap-assisted tunneling (TAT)---a commonly proposed transport mechanism in oxide- and nitride-based Schottky junctions---is discussed, while noting its role remains uncertain and not yet established in M/Nb:STO.

— Resistive Switching and Neuromorphic Computing in Metal/Nb:SrTiO$_3$: Mechanisms, Interface Physics, and Charge Transport  (2608.23430 - Broyles et al., 24 Aug 2026) in Section II, subsection “Trap-Assisted Tunneling”