Related Experiment Video
Updated: Jul 19, 2026
11:27
Single-Molecule Förster Resonance Energy Transfer Methods for Real-Time Investigation of the Holliday Junction Resolution by GEN1
Published on: September 18, 2019
Ultrafast hot-carrier dynamics at chemically modified Ge interfaces probed by SHG
Arthur McClelland1, Vasiliy Fomenko, Eric Borguet
1Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, USA.
The Journal of Physical Chemistry. B
|October 6, 2006
Summary
Time-resolved second-harmonic generation reveals faster carrier cooling at S- and Cl-terminated Germanium(111) interfaces. This impacts device degradation and the use of high-K dielectrics.
Area of Science:
- Materials Science
- Surface Science
- Optoelectronics
Background:
- Understanding hot-carrier dynamics is crucial for semiconductor device performance and longevity.
- Germanium (Ge) interfaces, particularly Ge(111), are vital in modern electronics.
- Surface termination significantly influences electronic and optical properties.
Purpose of the Study:
- To investigate hot-carrier dynamics at S-terminated and Cl-terminated Ge(111) interfaces.
- To determine the nonlinear optical properties of these interfaces on the femtosecond timescale.
- To compare carrier cooling rates with Ge(111)-GeO2 systems.
Main Methods:
- Time-resolved second-harmonic generation (SHG) spectroscopy.
- Femtosecond laser spectroscopy to probe ultrafast dynamics.
- Analysis of nonlinear optical susceptibilities.
Main Results:
- Hot-carrier nonlinear optical susceptibilities are significantly larger (720-880 times) than valence-band susceptibilities for Ge(111)-S and Ge(111)-Cl.
- Ground- and excited-state susceptibilities are out of phase, causing a pump-induced decrease in SHG signal.
- Faster SHG response times (172-220 fs) indicate accelerated carrier cooling compared to Ge(111)-GeO2 (415 fs).
Conclusions:
- Ge(111)-S and Ge(111)-Cl interfaces exhibit significantly faster carrier cooling.
- These findings have implications for mitigating hot-carrier-induced device degradation.
- The results suggest potential for improved device design using these terminated interfaces and high-K dielectrics.
