Unraveling delocalized electrons in metal induced gap states from second harmonics
Abstract
Second harmonic generation from Au-Al2O3 interfaces is analyzed to estimate the density of delocalized electrons occupying metal induced gap states (MIGS). Laser light of wavelength 810 nm is incident on an Au substrate and the second harmonic at 405 nm is monitored, where the area fraction of Al2O3 coverage on Au is precisely controlled via atomic layer deposition—from no coverage to full coverage. Extensive electromagnetic simulations are performed using a phenomenological model containing a dimensionless MIGS factor “α,” to represent the strength of the delocalized electrons in MIGS in attenuating the second harmonic signal. By fitting the model to experimental data, an α = 0.13 is obtained leading to a room temperature, areal density of delocalized electrons of (3.53 ± 0.4) × 1014 cm−2 for the Au-Al2O3 interface and representing a 44% occupancy of MIGS.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Oct 16, 2017
- Source ID
- 10.1063/1.4996893
Entities
People
- Andrew Sarangan
- Domenico De Ceglia
- Imad Agha
- Joseph W. Haus
- Mallik Mohd Raihan Hussain
- Maria A. Vincenti
- Michael Scalora
- Parag Banerjee
- Zhengning Gao
Organizations
- Army Research Office
- National Science Foundation
- United States Army
- University of Brescia
- University of Dayton
- Washington University in St. Louis