The influence of residual strain on Raman scattering in InxGa1−xAs single crystals

2006

Self Cite

Raman scattering (RS), photoluminescence (PL) and energy dispersive X-ray (EDX) experiments have been carried out to investigate residual strain and hence to understand breakage issue in bulk In x Ga 1-x As crystal grown by multi component zone melting (MCZM) method. It is found from a comparison that there is a large discrepancy among the RS, PL and EDX results due to the strain induced by compositional variation in the crystal. The strain induced changes in TO GaAs and PL peak positions are found to be 4.04 cm -1 and 0.097 eV, respectively, for the variation of composition from 0.06 to 0.29 from the seed-end to the tail-end of the crystal. By assuming a simple one-dimensional strain distribution, the strain value corresponding to 4.04 cm -1 / 0.097 eV can be obtained of the order of 10 -2 , which is large enough for understanding the breakage issue in the crystal investigated here.

Section: Comparison Between Raman and Edx Resultsmentioning

confidence: 58%

Section: Raman Resultsmentioning

confidence: 97%

Section: Experimental Methods For Residual Strain Investigationmentioning

confidence: 99%

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Spectroscopic investigation of strain induced by compositional variation in bulk InxGa1–xAs crystal grown by MCZM method

Rahman

Islam²,

2006

Self Cite

“…The shift in optical phonons in Raman spectra is induced due to the absolute value of composition for unstrained crystals [6]. On the other hand, the phonon position shifted both by strain and composition in presence of strain in the crystals [7,8]. Since the spectra are measured from Ga 1-x Mn x Sb/GaSb layers, the observed phonon positions should content composition-dependent shift and strain-induced shift.…”

Section: Resultsmentioning

confidence: 99%

“…On the other hand, the shift in optical phonons in Raman scattering (RS) is induced due to the composition in unstrained crystals [6]. In contrast, the optical phonons are shifted both by the composition and the strain in strained crystals [7,8]. Therefore, RS is a suitable non-destructive technique for simultaneous determination of composition and strain in the samples under investigation.…”

Section: Introductionmentioning

confidence: 99%

Raman scattering characterization of Mn composition and strain in Ga_1–xMn_x Sb/GaSb epitaxial layers

Mr¹,

Chen

2008

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Raman scattering (RS) experiments have been performed for simultaneous determination of Mn composition and strain in Ga 1-x Mn x Sb thin films grown on GaSb substrate by liquid phase epitaxy technique. The Raman spectra obtained from various Ga 1-x Mn x Sb samples show only GaSb-like phonon modes whose frequency positions are found to have Mn compositional dependence. With the combination of epilayer strain model, RS and energy dispersive x-ray (EDX) experiments, the compositional dependence of GaSb-like LO phonon frequency is proposed both in strained and unstrained conditions. The proposed relationships are used to evaluate Mn composition and strain from the Ga 1-x Mn x Sb samples. The results obtained from the RS data are found to be in good agreement with those determined independently by the EDX analysis. Furthermore, the frequency positions of MnSb-like phonon modes are suggested by reduced-mass model.

Raman scattering study on Ga_1–xMn_x As prepared by Mn ions implantation, deposition and post‐annealing

Islam¹,

Chen

2009

Self Cite

Raman scattering measurements have been performed in Ga 1−x Mn x As crystals prepared by Mn ions implantation, deposition, and post-annealing. The Raman spectrum measured from the implanted surface of the sample shows some weak phonon modes in addition to GaAs-like phonon modes, where the GaAs-like LO and TO phonons are found to be shifted by approximately 4 and 2 cm -1 , respectively, in the lower frequency direction compared to those observed from the unimplanted surface of the sample. The weak vibrational modes observed are assigned to hausmannite Mn 3 O 4 like. The coupled LO-phonon plasmon mode (CLOPM), and defects and As related vibrational modes caused by Mn ions implantation, deposition, and post-annealing are also observed. The compositional dependence of GaAs-like LO phonon frequency is developed for strained and unstrained conditions and then using the observed LO GaAs peak, the Mn composition is evaluated to be 0.034. Furthermore, by analyzing the intensity of CLOPM and unscreened LO GaAs phonon mode, the hole density is evaluated to be 1.84×1018 cm -3 .