First-order Raman line intensity ratio in GaAs: a potential lattice perfection scale

Articles you may be interested inHigh-pressure Raman scattering in InGaN heteroepitaxial layers: Effect of the substrate on the phonon pressure coefficients Appl. Phys. Lett.Strain and thermal effects on longitudinal and transverse optical ͑LO͒ and ͑TO͒ phonon frequencies and on associated electron-phonon interactions have been analyzed in GaAs. We focus separately on these effects to treat each one thoroughly. By using lattice-mismatched ͗111͘ Si or CaF 2 substrates, GaAs layers with highly tensile or compressive strain have been analyzed. We show that the LO/TO Raman scattering efficiency ratio, i.e., the electro-optic versus the atomic displacement electron-phonon mechanisms, varies with the built-in strain and hence its induced piezoelectric field. The Raman selection rules are valid in this process. The increase and decrease of this ratio compared to a reference suggest an interference effect. We discuss this phenomenon on the basis of strain-induced Raman scattering.

Section: Faust-henry Coefficient Temperature Dependence C(t)supporting

confidence: 87%

“…In an unstrained crystal, the relative magnitude of the atomic displacement contribution versus the electro-optic one is expressed using the Faust-Henry coefficient, C, defined by 10,11 Cϭ e* TO…”

Section: A Raman Spectrum From Zinc-blende Materialsmentioning

confidence: 99%

Strain effects on optical phonons in 〈111〉 GaAs layers analyzed by Raman scattering

Puech

Landa

Carles

et al. 1997

“…Thus, a small disorientation should be introduced leading to a mixing of the Raman tensors. Equation (14) contains all the degrees of freedom possessed in a standard Raman backscattering measurement. For b angles of 0 and 1=p;ê i andê s will be parallel and perpendicular, respectively.…”

mentioning

confidence: 99%

Polarized Raman backscattering selection rules for (hhl)-oriented diamond- and zincblende-type crystals

Steele

Puech

Lewis

2016

. (2016). Polarized Raman backscattering selection rules for (hhl)-oriented diamond-and zincblende-type crystals. Journal of Applied Physics, 120 (5), 055701-1-055701-6. Polarized Raman backscattering selection rules for (hhl)-oriented diamond-and zincblende-type crystals AbstractDue to their interesting orientation-dependent properties, the ability to grow high-index semiconductor crystals and nanostructures extends the design palette for applications based on these materials. Notably, a source containing a systematic reporting of what the Raman tensors are for an arbitrary high-index zincblende material is yet to appear in the literature. Herein, we present the polarized Raman backscattering selection rules for arbitrary (hhl)-oriented diamond-and zincblende-type crystal surfaces and verify their correctness through experiment (up to (115)). Considering the many degrees of freedom available to common polarized micro-Raman scattering instruments, and the unique local orientation of the probed material, we further examine a range of consequences imposed by the selection rules for the Raman backscattering method. Due to their interesting orientation-dependent properties, the ability to grow high-index semiconductor crystals and nanostructures extends the design palette for applications based on these materials. Notably, a source containing a systematic reporting of what the Raman tensors are for an arbitrary high-index zincblende material is yet to appear in the literature. Herein, we present the polarized Raman backscattering selection rules for arbitrary (hhl)-oriented diamond-and zincblende-type crystal surfaces and verify their correctness through experiment (up to (115)). Considering the many degrees of freedom available to common polarized micro-Raman scattering instruments, and the unique local orientation of the probed material, we further examine a range of consequences imposed by the selection rules for the Raman backscattering method. Published by AIP Publishing.

“…[13][14][15] This effect has been attributed to a partial relaxation of the momentum selection rule and subsequent activation of phonon modes around the center of the Brillouin zone. [13][14][15] This effect has been attributed to a partial relaxation of the momentum selection rule and subsequent activation of phonon modes around the center of the Brillouin zone.…”

Section: Discussionmentioning

confidence: 99%

Structural properties of ZnSe epilayers on (111) GaAs

Kontos

Chrysanthakopoulos

Calamiotou

et al. 2001

Structural and optical studies of ZnSe epilayers, which were grown on the B side of ͑111͒-oriented GaAs substrates, indicate the presence of tensile in-plane strains in the epilayers at room temperature. Electron microscopy observations showed that the ZnSe epilayer forms a coherent sharp interface with the GaAs substrate and consists of crystallites which are grown in epitaxial or twin orientation with respect to the substrate, having the ͑111͒ planes oriented parallel to the interface. In addition, embedded twins are observed within the epilayer. The twin boundaries are, generally, terminated by Shockley partial dislocations, which are expected to relax the compressive lattice mismatch strain. Plastic or thermal relaxation cannot account for sign and magnitude of the observed strains. Evidence is found that the observed tensile strains are piezoelectrically induced in a depletion layer, due to Fermi level pinning at the ZnSe/GaAs interface.