Raman Spectroscopy as a Tool for Characterization of Strained Hexagonal GaN/AlxGa1?xN Superlattices

Abstract

PACS: 78.30.FsIt is shown that such parameters of GaN/Al x Ga 1--x N superlattice as the period, built-in strain, composition of the alloy, and individual layer thicknesses can be extracted from the energy positions, intensities, and line shapes of various optical and acoustic modes detected in Raman scattering.Computer Simulation Phonon frequencies and phonon eigendisplacements for GaN m /AlN n SLs (n þ m ¼ 20) have been calculated within the frame of an extended Bom-Karman model. Consideration of the long-range Coulomb interaction has been carried out in the dipole approximation within the model of 'rigid ions'. The Raman phys. stat. sol. (b) 234, No. 3, 975-979 (2002)

Electrochemical Aspects and Structure Characterization of VA-VIA Compound Semiconductor Bi2Te3/Sb2Te3 Superlattice Thin Films via Electrochemical Atomic Layer Epitaxy

“…However, the red shift of the mode at 260 cm −1 should be related to the interior strain after anneal. Namely, because of the different thermo-expanded coefficient between Bi 2 Te 3 and Sb 2 Te 3 , the expanded strain would come into being in the interface of annealed superlattice sample and resulting to the red shift of the mode. , The property of red shift suggested that the mode at 260 cm −1 belonged to different categories of mode. Similarly, the blue shift of the mode at 645 cm −1 should also attribute to the effect of ternary alloys.…”

Raman scattering by folded acoustic phonons in InGaN/GaN superlattices

“…The observation of two doublets in the samples with lower In content, up to x = 23%, is a consequence of the high crystal and interface quality of these SLs. Note that, in previous Raman studies on GaN/Al 0.28 Ga 0.72 N SLs, only the first folded doublet was detected 7, 8…”

“…The wavenumber, as well as splitting of the folded modes, is linked to the dispersion of the acoustic phonon modes and to the sound velocities of the layers. In the case of III‐nitrides, Raman scattering by folded acoustic modes has been used to characterize the period of GaN/Al 0.28 Ga 0.72 N SLs 7, 8. In spite of the large interest of InGaN‐based SLs both from fundamental and applications points of view, very little data on the vibrational properties of InGaN/GaN SLs has been published so far.…”

Spectrochemical Technology in Nanomaterial Preparation and Art Appraisal Technology Research

“…e average spectrum of the set to be modified is the ideal spectrum. Each spectrum has an ideal spectrum and linear relationship, so the calculation based on the inclination of the line can be obtained by linear regression [16]. By the mathematical method, the scattering signal of the sample spectrum is separated from the internal component information of the sample, and the random variation is eliminated as much as possible.…”