Evidence for anisotropic dielectric properties of monoclinic hafnia using valence electron energy-loss spectroscopy in high-resolution transmission electron microscopy and ab initio time-dependent density-functional theory

Journal Article · Mon Dec 01 00:00:00 EST 2014 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4903218· OSTI ID:22402421

Guedj, C. ^[1]; Hung, L.; Sottile, F. ^[2]; Zobelli, A. ^[3]; Blaise, P. ^[1]; Olevano, V. ^[1]

---

1. University Grenoble Alpes, F-38000 Grenoble (France)
2. LSI, CNRS, CEA, École Polytechnique, F-91128 Palaiseau (France)
3. LPS, CNRS and University Paris Sud, F-91405 Orsay (France)

The effect of nanocrystal orientation on the energy loss spectra of monoclinic hafnia (m-HfO{sub 2}) is measured by high resolution transmission electron microscopy (HRTEM) and valence energy loss spectroscopy (VEELS) on high quality samples. For the same momentum-transfer directions, the dielectric properties are also calculated ab initio by time-dependent density-functional theory (TDDFT). Experiments and simulations evidence anisotropy in the dielectric properties of m-HfO{sub 2}, most notably with the direction-dependent oscillator strength of the main bulk plasmon. The anisotropic nature of m-HfO{sub 2} may contribute to the differences among VEELS spectra reported in literature. The good agreement between the complex dielectric permittivity extracted from VEELS with nanometer spatial resolution, TDDFT modeling, and past literature demonstrates that the present HRTEM-VEELS device-oriented methodology is a possible solution to the difficult nanocharacterization challenges given in the International Technology Roadmap for Semiconductors.

• OSTI ID: 22402421
• Journal Information: Applied Physics Letters, Vol. 105, Issue 22; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DENSITY FUNCTIONAL METHOD
DIELECTRIC MATERIALS
ENERGY-LOSS SPECTROSCOPY
HAFNIUM OXIDES
MOMENTUM TRANSFER
MONOCLINIC LATTICES
NANOSTRUCTURES
OSCILLATOR STRENGTHS
PERMITTIVITY
SEMICONDUCTOR MATERIALS
SIMULATION
TIME DEPENDENCE
TRANSMISSION ELECTRON MICROSCOPY