Porosity-Induced Optical Phonon Engineering in III-V Compounds

1998 ◽  
Vol 536 ◽  
Author(s):  
I. M. Tiginyanu ◽  
G. Irmer ◽  
J. Monecke ◽  
H. L. Hartnagel ◽  
A. Vogt ◽  
...  
Keyword(s):  
Optical Phonon ◽  
Phonon Frequency ◽  
Vibrational Mode ◽  
Longitudinal Optical ◽  
Electrochemical Anodization ◽  
Raman Analysis ◽  
Porous Layers ◽  
Surface Phonon ◽  
Promising Tool ◽  
Phonon Spectra

AbstractNew possibilities for modifying the phonon spectra of III-V compounds are evidenced by micro-Raman analysis of porous layers prepared by electrochemical anodization of (111 )Aoriented n-GaP substrates. In particular, a surface-related vibrational mode along with a porosity-induced decoupling between the longitudinal optical (LO) phonon and plasmon are observed. We prove that filling in the pores with other materials (aniline as a first approach) is a promising tool for controlling the surface phonon frequency.

Raman analysis of longitudinal optical phonon-plasmon coupled modes of aligned ZnO nanorods

2009 ◽  
Vol 105 (7) ◽  
pp. 073104 ◽  
Author(s):  
An-Jen Cheng ◽  
Yonhua Tzeng ◽  
Hui Xu ◽  
Siddharth Alur ◽  
Yaqi Wang ◽  
...  
Keyword(s):  
Optical Phonon ◽  
Zno Nanorods ◽  
Longitudinal Optical ◽  
Longitudinal Optical Phonon ◽  
Coupled Modes ◽  
Raman Analysis

Electron–Interface–Phonon Interaction and Magnetopolaronic Impurity Transitions in Quantum Wells

1997 ◽  
Vol 11 (08) ◽  
pp. 991-1008 ◽  
Author(s):  
R. Chen ◽  
D. L. Lin
Keyword(s):  
Quantum Wells ◽  
Optical Phonon ◽  
Phonon Frequency ◽  
Transition Energy ◽  
Bulk Sample ◽  
Longitudinal Optical ◽  
Longitudinal Optical Phonon ◽  
Phonon Modes ◽  
Phonon Interaction ◽  
Double Heterostructure

The polaronic effect on the hydrogenic 1s–2p+ transition energy of a donor impurity located at the quantum well center in a double heterostructure is studied theoretically in detail. The electron–optical–phonon interaction Hamiltonian is derived on the basis of eigenmodes of lattice vibrations supported by the double heterostructure. Both the confined and interface phonon modes are included in the electron–phonon coupling. The transition energy is calculated as a function of the applied magnetic field for GaAs/Al 1-x Ga x As samples of well -widths d=125 Å, 210 Å and 450 Å by the second-order perturbation. Wide transition gaps are predicted around the two-level and three-level resonances for all three cases. It is found that the transition gap narrows with the increasing well-width but remains larger than the LO and TO phonon frequency difference for d=450 Å as is observed. We also perform the same calculation by assuming that the confined electron interacts with three-dimensional and two-dimensional phonon modes. The transition energy spectra from these calculations appear to be similar to those for a bulk sample, the spectrum splits at the resonance with the longitudinal optical phonon frequency only. From comparisons of our results with these calculations as well as with experiments, it is conclusively established that the wide gap of transition energy is solely due to the interface modes.

Application of the nonuniform-field treatment to the infrared properties of LiF

1969 ◽  
Vol 47 (1) ◽  
pp. 51-64 ◽  
Author(s):  
A. J. Beaulieu
Keyword(s):  
Thin Films ◽  
Optical Phonon ◽  
Phonon Frequency ◽  
Quantitative Agreement ◽  
Longitudinal Optical ◽  
Optical Frequency ◽  
Nonuniform Field ◽  
Optical Phonon Frequency ◽  
Experimental Values ◽  
Comparison Of The Results

The "nonuniform-field treatment" developed earlier for infinitely thick crystals is applied to the LiF crystal. Comparison with experimental results both at 45° and at small angles of incidence gives good quantitative agreement only when the ratio of the longitudinal optical frequency to the transverse optical frequency is assumed to be 1.7 instead of 2.2 as predicted by the Lyddane–Sach–Teller relation. An extension of the treatment to thin films is presented and the comparison of the results with Berreman's experimental values indicates that the asymmetry and the amplitude of the features which could not be explained before can be predicted in terms of the nonuniform-field treatment, again provided the optical phonon frequency ratio is 1.7.

scholarly journals The influence of atoms of second coordination sphere on phonon dispersion of diamond

2020 ◽  
pp. 111-113
Author(s):  
V. A. Sachkov ◽  
Keyword(s):  
Raman Scattering ◽  
Interaction Energy ◽  
Coordination Sphere ◽  
Phenomenological Model ◽  
Optical Phonon ◽  
Phonon Frequency ◽  
Phonon Dispersion ◽  
Longitudinal Optical ◽  
Optical Phonons ◽  
Second Coordination Sphere

Within the framework of the phenomenological model of twoparticle interaction, the effect of the interaction energy of atoms from the second coordination sphere on the phonon dispersion is considered. This approach makes it possible to vary the growth of the phonon frequency relative to the optical phonon in the center of the Brillun zone. The effects of the contribution to the Raman spectra from longitudinal optical phonons with frequencies higher than their frequency at the center of the Brillouin zone are discussed. The contribution to the frequency of interaction of atoms from the second coordination sphere for some phonons is obtained in an explicit form. The formulas obtained will be useful for calculating the spectra of Raman scattering of light by optical phonons localized in diamond nanocrystals

Micro-Raman Study of Charge Carrier Distribution and Cathodoluminescence Microanalysis of Porous gap Membranes

1999 ◽  
Vol 588 ◽  
Author(s):  
I. M. Tiginyanu ◽  
M. A. Stevens Kalceff ◽  
A. Sarua ◽  
G. Irmer ◽  
J. Monecke ◽  
...  
Keyword(s):  
Longitudinal Optical ◽  
Sulphuric Acid Solution ◽  
Porous Membranes ◽  
Specific Information ◽  
Carrier Distribution ◽  
Free Standing ◽  
Raman Analysis ◽  
Porous Layers ◽  
Emission Efficiency ◽  
Raman Study

AbstractPorous layers and free-standing membranes were fabricated by anodic etching of n-GaP substrates in a sulphuric acid solution. Micro-Raman analysis of the interaction between the longitudinal optical phonons and plasmons in porous membranes allowed us to obtain specific information about the electro-optical properties of microstructured GaP. In particular, apart from the carrier exhausted areas surrounding the pores, the existence of conductive regions was demonstrated. A comparative analysis of the secondary electron and panchromatic cathodoluminescence (CL) images evidenced an increase in the emission efficiency caused by porosity. Data concerning the spectral distribution of CL in bulk and porous samples are presented.

Strain Shift Coefficients for Phonons in Si-Ge Heterostructures

1991 ◽  
Vol 239 ◽  
Author(s):  
J.-M. Baribeau ◽  
D. J. Lockwood
Keyword(s):  
Molecular Beam ◽  
Composition Dependence ◽  
Vibration Mode ◽  
Phonon Frequency ◽  
Longitudinal Optical ◽  
Stress Factor ◽  
Double Crystal ◽  
Raman Scattering Spectroscopy ◽  
X Ray ◽  
Shift Coefficient

ABSTRACTStrain shift coefficient measurements for longitudinal optical phonons in molecular beam epitaxy grown metastable pseudomorphic Si1−xGex layers on (100) Si (0 < x < 0.35) and Ge (0.80 < x < 1) are reported. Strain in partially relaxed annealed specimens was obtained by double-crystal x-ray diffractometry and the corresponding strain phonon shift was measured by Raman scattering spectroscopy. For epilayers grown on Si it was found that the epilayer Si-Si phonon frequency varies linearly with strain. The magnitude of the strain shift coefficient b however showed a small composition dependence varying from b ≈ -700 cm-1 at x = 0 to b ≈ -950 cm-1 at x = 0.35, corresponding to a stress factor τ = 0.40 + 0.57x: + 0.13x2 cm-1/kbar. For the Ge-Ge vibration mode in epilayers grown on Ge, b decreased from ∼-425 cm-1 at x = 1 to ∼-500 cm-1 at x = 0.8, corresponding to a stress factor τ ≈ 0.52 – 0.14x - 0.08x2 cm-1/kbar.

Optical phonon spectra of GaSb/AlSb superlattices: Influence of strain and interface roughnesses

1996 ◽  
Vol 80 (1) ◽  
pp. 597-599 ◽  
Author(s):  
S. W. da Silva ◽  
Yu. A. Pusep ◽  
J. C. Galzerani ◽  
D. I. Lubyshev ◽  
A. G. Milekhin ◽  
...  
Keyword(s):  
Optical Phonon ◽  
Phonon Spectra
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