Work Function Control of Germanium through Carborane-Carboxylic Acid Surface Passivation
Andrew C Serino, Mary E Anderson1, Liban M A Saleh
1Department of Chemistry and Biochemistry, Hope College , Holland, Michigan 49423, United States.
ACS Applied Materials & Interfaces
|September 19, 2017
Summary
Self-assembled monolayers (SAMs) of carborane molecules were used to modify germanium surfaces. Carboxylic acid head groups enabled successful film formation, tuning the surface work function without altering wetting properties.
Area of Science:
- Materials Science
- Surface Chemistry
- Nanotechnology
Background:
- Self-assembled monolayers (SAMs) are crucial for surface functionalization.
- Germanium (Ge) surface modification is essential for electronic applications.
- Understanding head group reactivity on novel surfaces is key.
Purpose of the Study:
- To investigate carborane-based SAMs for passivating germanium surfaces.
- To explore the influence of carborane structure on head group reactivity.
- To modulate the germanium surface work function using carborane SAMs.
Main Methods:
- Formation and characterization of thiol-, hydroxyl-, and carboxyl-terminated carborane SAMs on germanium.
- Utilized X-ray and ultraviolet photoelectron spectroscopies (XPS and UPS).
- Employed contact angle goniometry for surface wetting analysis.
Main Results:
- Carboxylic acid head groups successfully formed SAMs on germanium, unlike typical thiol-based SAMs.
- The carborane cluster significantly influenced the head group's chemical reactivity.
- Germanium surface work function was successfully tuned by over 0.4 eV.
- Wetting properties of the germanium surface remained largely unchanged.
Conclusions:
- Carborane-based SAMs offer a viable route for germanium surface modification.
- Carboxylic acid terminated carboranes are effective for forming monolayers on germanium.
- This approach allows for precise control over germanium surface properties, including work function, without compromising surface energy.
