Submillimeter-Sized Neodymium Oxychloride Single-Crystal Dielectrics for 2D Electronics

Area of Science:

• Materials Science
• Nanotechnology
• Solid State Physics

Background:

• Atomically thin semiconductors and 2D dielectrics are crucial for overcoming scaling limitations in nanoelectronics.
• Current 2D dielectrics face challenges including low dielectric constants, poor interface quality, and limited gate control.
• Advancements in gate dielectric materials are essential for next-generation electronic devices.

Purpose of the Study:

• To synthesize and characterize novel single-crystal neodymium oxychloride (NdOCl) nanosheets for use as 2D gate dielectrics.
• To evaluate the performance of NdOCl as a dielectric layer in field-effect transistors (FETs) based on molybdenum disulfide (MoS2).
• To demonstrate the potential of NdOCl for fabricating advanced, miniaturized nanoelectronic devices.

Main Methods:

• Controlled synthesis of single-crystal NdOCl nanosheets using a modified physical vapor deposition (PVD) approach.
• Characterization of NdOCl nanosheets for dielectric properties, including dielectric constant, leakage current, and bandgap.
• Fabrication and testing of MoS2/NdOCl field-effect transistors (FETs) and logic inverters.

Main Results:

• Submillimeter-sized (169 µm) and ultrathin (5 nm) NdOCl nanosheets were successfully synthesized.
• NdOCl exhibits a high dielectric constant (κ≈11.7), ultralow leakage current (≈10⁻⁷ A cm⁻²), and a wide bandgap (4.57 eV).
• MoS2/NdOCl FETs demonstrated high on/off ratios (10⁸), steep subthreshold swings, suppressed Coulomb scattering, and enhanced carrier mobility (123 cm²/V·s at 80 K).
• Short-channel MoS2 FETs (100 nm) and high-gain logic inverters (60.9) were successfully fabricated using NdOCl dielectrics.

Conclusions:

• NdOCl is a promising high-κ 2D dielectric material for advanced nanoelectronic applications.
• The improved dielectric properties and interfacial quality of NdOCl enable superior transistor performance.
• NdOCl facilitates the development of miniaturized electronic devices with enhanced functionality and efficiency.