Pulsed Force Kelvin Probe Force Microscopy through Integration of Lock-In Detection

Area of Science:

• Materials Science
• Surface Science
• Nanotechnology

Background:

• Kelvin probe force microscopy (KPFM) is crucial for analyzing nanoscale electronic properties like surface potential.
• Pulsed force KPFM (PF-KPFM) offers high resolution but suffers from complexity and slow operation.
• Existing methods struggle to reveal subtle electrical degradation in sensitive materials.

Purpose of the Study:

• To develop a simplified and accelerated PF-KPFM technique.
• To overcome the limitations of instrument complexity and operational speed in PF-KPFM.
• To demonstrate the enhanced capabilities for analyzing electronic properties of advanced materials.

Main Methods:

• Implementation of a lock-in amplifier with phase-synchronized field effect transistor switching.
• Mediation of Coulombic force between the KPFM probe and sample.
• Application to two-dimensional MXene and aged perovskite photovoltaic films.

Main Results:

• The lock-in-based PF-KPFM method significantly reduces instrument complexity and increases operational speed.
• Distinct contact potential differences (CPDs) were identified between monoflake and multiflake MXene.
• Electrical degradation in perovskite films was detected, which was not visible through surface topography alone.

Conclusions:

• The lock-in amplifier-based PF-KPFM provides a more accessible and efficient approach for nanoscale electronic characterization.
• This technique offers valuable insights into material properties and degradation mechanisms.
• It holds promise for advancing the study of 2D materials and organic electronics.