Lattice Defect Engineering Enables Performance-Enhanced MoS2 Photodetection through a Paraelectric BaTiO3 Dielectric

Carrier mobility and density are intrinsically important in nanophoto/electronic devices. Highdielectric-constant coupled polarization-field gate ferroelectrics are frequently studied and partially capable in achieving large-scale tuning of photoresponse, but their light absorption and carrier density seem generally ineffective. This raises questions about whether a similarly high-dielectric-constant paraelectric gate dielectric could enable tuning and how the principles involved could be established. In this study, by deliberately introducing lattice defects in high-dielectric-constant paraelectric, cubic BaTiO3 (c-BTO) was explored to fabricate MoS2 photodetectors with ultrahigh detection ability and outstanding field-effect traits. An organic-metal-based spincoating cum annealing method was used for the c-BTO synthesis, with an optimized thickness (300 nm), by introducing lattice defects properly but maintaining a large dielectric constant (55 at 1k Hz) and low dielectric loss (0.06 at 1k Hz), which renders the enhanced visible-light region absorption. As a result of the synergistically enhanced mobility and photoabsorption, the MoS2/BTO FET exhibits promising merits, for example, on/off ratio, subthreshold swing, and mobilities for high-performance photodetectors with excellent responsivity (600 AW-1) and detectivity (1.25 x 10(12) Jones). Thus, this work facilitates the establishment of a lattice defect induced sub-bandgap absorption landmap for synergistically enhanced photoresponse for high-performance photodetector exploration.

Automated summary

In this study, lattice defects were deliberately introduced in high-dielectric-constant paraelectric cubic BaTiO3 to fabricate MoS2 photodetectors with ultrahigh detection ability and outstanding field-effect traits. An organic-metal-based spincoating cum annealing method was used for material synthesis, with optimized thickness, high dielectric constant, and low dielectric loss, resulting in enhanced visible-light absorption. The synergistically enhanced mobility and photoabsorption in the MoS2/BTO FET demonstrate promising merits for high-performance photodetectors with excellent responsivity and detectivity.