Carrier Density-Dependent Localized Surface Plasmon Resonance and Charge Transfer Observed by Controllable...

Area of Science:

• Materials Science
• Nanotechnology
• Surface Chemistry

Background:

• Localized surface plasmon resonance (LSPR) is crucial for nanophotonics.
• Charge transfer (CT) mechanisms are vital for understanding interfacial electronic processes.
• Tuning plasmonic properties in composite materials remains an active research area.

Purpose of the Study:

• To investigate the influence of controllable carrier density on LSPR and CT in a Ag and Cu2S composite system.
• To establish a relationship between sputtering power, carrier density, LSPR tuning, and CT.
• To provide a guideline for tunable LSPR and CT investigations.

Main Methods:

• Fabrication of Ag and Cu2S composite substrates with varying Cu2S sputtering power.
• Ultraviolet-visible spectroscopy to measure LSPR peak shifts.
• Surface-enhanced Raman scattering (SERS) to probe charge transfer.
• Hall effect measurements to characterize carrier density.

Main Results:

• LSPR peak was tunable from 580 to 743 nm by adjusting Cu2S sputtering power.
• LSPR showed a direct proportionality to the Cu2S sputtering power, indicating control via semiconductor content and carrier density.
• Carrier density was characterized, and its relationship with Raman shift (indicating CT) was established.

Conclusions:

• The sputtering power of Cu2S in Ag and Cu2S composites offers a precise method for tuning LSPR.
• Carrier density is a key factor influencing both LSPR and CT in these systems.
• The findings provide fundamental insights for designing tunable plasmonic materials and understanding interfacial charge dynamics.