Strain-induced effects on the dielectric constant for thin, crystalline rare earth oxides on silicon

Abstract

Thin epitaxial rare earth oxide layers on Si exhibit K values that are much larger than the known bulk values. We investigate the thickness dependence of that enhancement effect for epitaxial Gd2O3 on Si(111). Controlling the oxide composition in ternary (Gd1-xNdx)2O3 thin films enables us to tune the lattice mismatch to silicon and thus the K values of the dielectric layer from 13 (close to the bulk value) up to 20. We show that simple tetragonal distortion of the cubic lattice is not sufficient to explain the enhancement in K. Therefore, we propose more severe strain induced structural phase deformations.

Interference-Modulated Excitonic Reflectance of Monolayer MoSe2 on Epitaxial Gd2O3 Thin Films

“…12,57,58 Further, the dielectric constant of Gd 2 O 3 thin films in the thickness range considered for the present study does not vary significantly. 59 Therefore, in this study, it is not expected to observe any significant shift in the peak positions or the fwhm of the emission or reflectance peaks with changing the thickness of the epitaxial Gd 2 O 3 layers, which have very low surface roughness.…”

“…It is evident from Figure that increase of the epitaxial Gd 2 O 3 layer thickness does not have any significant impact on resonant energy and line width of the excitonic oscillators in the MoSe 2 MLs. Dielectric substrate thickness might influence the screening of the excitons in the TMDCs; however, modification of the exciton binding energy often compensates for the modification in the band gap, which renders the peak positions of the excitons relatively unchanged in many cases. ,, Further, the dielectric constant of Gd 2 O 3 thin films in the thickness range considered for the present study does not vary significantly . Therefore, in this study, it is not expected to observe any significant shift in the peak positions or the fwhm of the emission or reflectance peaks with changing the thickness of the epitaxial Gd 2 O 3 layers, which have very low surface roughness.…”

(Invited) Tuning Dielectric Properties of Epitaxial Lanthanide Oxides on Silicon

“…First, we will investigate the influence of lattice strain on the dielectric constant for gadolinium oxide (9). Thin Gd 2 O 3 layers with thicknesses between 3.8 nm and 23 nm were grown on (111)-oriented Si substrates at a substrate temperature of 650°C in a multi-chamber solid source Molecular Beam Epitaxy (MBE) system.…”

Investigation of the excitations of plasmons and surface exciton polaritons in monoclinic gadolinium sesquioxide by electron energy-loss spectroscopy and plasmon spectroscopic imaging

“…6,7 Most recently, monoclinic phase Gd 2 O 3 (m-Gd 2 O 3 , space group of C2/m) was stabilized in the thin lms and the bulk form via epitaxial growth on a GaN substrate 8 and by doping during the fabrication processes. 9 Most importantly, the k value of m-Gd 2 O 3 was higher than 20 due to its crystal symmetry, 10 which leads to an essential improvement of the EOT values. Therefore, a deeper understanding of the electronic band structure, including bandgap and band offset for m-Gd 2 O 3 lm/semiconductor heterostructures, becomes crucial for further CMOS and MOSFET microelectronic technology applications.…”