Au/ITO dual-layer-coated optical fiber probe for multifunctional scanning tunneling microscopy

Area of Science:

• Nanotechnology
• Materials Science
• Surface Science

Background:

• Scanning tunneling microscopy (STM) is a powerful tool for surface imaging at the atomic level.
• STM-induced electroluminescence (STML) allows for optical detection of electronic processes on surfaces.
• Developing advanced probes is crucial for improving the resolution and functionality of these techniques.

Purpose of the Study:

• To fabricate and characterize a novel dual-layer Au/ITO optical fiber probe.
• To evaluate the probe's performance for high-quality STM imaging.
• To assess the probe's capability for near-field excitation and detection of STML.

Main Methods:

• Fabrication of a dual-layer optical fiber probe with an inner indium-tin-oxide (ITO) layer for conductivity and an outer gold (Au) layer for enhanced performance.
• Utilizing the fabricated probe for STM imaging and STML measurements on Au(111)/mica and p-GaAs(110) surfaces at room temperature.
• Analyzing the impact of the outer Au layer on imaging quality, probe durability, STML stability, and light emission enhancement.

Main Results:

• High-quality STM images were obtained on both Au(111)/mica and p-GaAs(110) surfaces.
• STML measurements yielded maximum quantum efficiencies of 7 x 10(-4) and 1 x 10(-4) photons/electron, respectively.
• The outer Au layer significantly improved STM imaging quality, probe durability, STML stability, and enhanced plasmon-mediated STML on the Au(111) surface.

Conclusions:

• The Au/ITO dual-layer optical fiber probe is effective for high-quality STM imaging and STML.
• The outer Au layer plays a critical role in enhancing probe performance and plasmon-mediated light emission.
• This probe offers a promising platform for advanced surface characterization and optoelectronic studies.