This study explores the switching behavior of sliding ferroelectricity in ferroelectric tunnel junctions (FTJs) with composite ferroelectric/non-polar insulator barriers. The research focuses on twisted rhombohedral bilayers of transition metal dichalcogenides (TMDs), where interfacial ferroelectricity is observed. Using scanning probe microscopy and tunneling transport measurements, the authors demonstrate ambipolar switching behavior in FTJs, with ON/OFF ratios exceeding 10. The switching behavior is strongly influenced by the underlying domain structure, enabling the fabrication of diverse FTJ devices with various functionalities. The study shows that polarization reversal requires at least one partial dislocation in the device area, a behavior distinct from conventional ferroelectric materials. The research highlights the importance of understanding sliding ferroelectricity for future optoelectronic devices. The study also discusses the challenges of engineering atomically thin metal-oxide ferroelectrics due to instability, interface chemistry, and high contact resistances. The authors demonstrate that 2D materials are promising candidates for next-generation (opto-)electronic devices due to their thickness limit and immunity to depolarization. The study presents various examples of intrinsic 2D ferroelectricity in materials such as SnTe, MoTe2, WTe2, and CuInP2S6. The research also explores the engineering of ferroelectric interfaces with broken inversion symmetry to achieve interfacial ferroelectricity in twisted homo-bilayers of insulating hBN and TMDs. The study shows that the switching behavior in FTJs is significantly different from conventional ferroelectric materials, with the observed behavior being dependent on the local domain structure. The authors also discuss the role of domain walls in ferroelectric switching, and the importance of understanding the energy trade-off between domain wall extension and bending. The study concludes that the switching behavior in FTJs is highly sensitive to the location of the junction, and that a single domain boundary must pre-exist within the device area for full switching. The research provides insights into the potential of sliding ferroelectricity for future optoelectronic devices.This study explores the switching behavior of sliding ferroelectricity in ferroelectric tunnel junctions (FTJs) with composite ferroelectric/non-polar insulator barriers. The research focuses on twisted rhombohedral bilayers of transition metal dichalcogenides (TMDs), where interfacial ferroelectricity is observed. Using scanning probe microscopy and tunneling transport measurements, the authors demonstrate ambipolar switching behavior in FTJs, with ON/OFF ratios exceeding 10. The switching behavior is strongly influenced by the underlying domain structure, enabling the fabrication of diverse FTJ devices with various functionalities. The study shows that polarization reversal requires at least one partial dislocation in the device area, a behavior distinct from conventional ferroelectric materials. The research highlights the importance of understanding sliding ferroelectricity for future optoelectronic devices. The study also discusses the challenges of engineering atomically thin metal-oxide ferroelectrics due to instability, interface chemistry, and high contact resistances. The authors demonstrate that 2D materials are promising candidates for next-generation (opto-)electronic devices due to their thickness limit and immunity to depolarization. The study presents various examples of intrinsic 2D ferroelectricity in materials such as SnTe, MoTe2, WTe2, and CuInP2S6. The research also explores the engineering of ferroelectric interfaces with broken inversion symmetry to achieve interfacial ferroelectricity in twisted homo-bilayers of insulating hBN and TMDs. The study shows that the switching behavior in FTJs is significantly different from conventional ferroelectric materials, with the observed behavior being dependent on the local domain structure. The authors also discuss the role of domain walls in ferroelectric switching, and the importance of understanding the energy trade-off between domain wall extension and bending. The study concludes that the switching behavior in FTJs is highly sensitive to the location of the junction, and that a single domain boundary must pre-exist within the device area for full switching. The research provides insights into the potential of sliding ferroelectricity for future optoelectronic devices.