Long-wavelength optical phonon properties of ternary MgZnO thin films

Chen, J.; Shen, Wei

doi:10.1063/1.1610795

Cited by 43 publications

(23 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In order to interpret these results semiquantitatively, we resort to the original MREI model proposed by Chang et al 2,5 At the same time, some modifications have to be adopted. In MREI, first, it assumes that the cation and anion of like species vibrate as a rigid unit, i.e., the units vibrate with the same phase and amplitude.…”

Section: Whenmentioning

confidence: 99%

See 1 more Smart Citation

Raman scattering of indium-richAlxIn1−xN: Unexpected two-mode behavior of
Kang
¹
,
Hashimoto
²
,
Yamamoto
³

2009
Phys. Rev. B
24
3
10
0
View full text Add to dashboard Cite

Al x In 1−x N films ͑0.03Յ x Յ 0.80͒, particularly indium-rich AlInN films, are studied by Raman scattering. We clearly observe a two-mode behavior of A 1 ͑LO͒ phonon and prove that the previous theoretical prediction and experimental attribution of InN-like A 1 ͑LO͒ to E 2 H mode are incorrect. Using the modified random-element isodisplacement model of Chang and Mitra, the information about AlInN lattice vibration is extracted. We believe that these results imply a strong positive force interaction between In and Al sublattices in AlInN. The strong interaction makes AlInN different with AlGaN in A 1 ͑LO͒ phonon mode behavior.The lattice dynamics of random alloys is a complex issue. The complexity results from the interplay of different lattice bonds due to composition variation. An important phenomenon in this field is the mode behavior of long-wavelength optical phonons. It is known that ternary mixed crystals A x B 1−x C with fully pronounced random alloy character are classified into two main classes according to the behavior of zone-center optical phonons. In the one-mode class, the frequencies vary continuously and approximately linearly with the molar fraction x of the alloy. In the case of two-mode behavior, there are two sets of optical modes corresponding nearly to those of two pure crystals AC or BC which compose the alloy. These extra modes may persist very close to the end compositions, i.e., x = 0 and x =1. 1 In order to determine the mode behavior of longwavelength optical phonons in mixed crystals, using the modified random-element isodisplacement ͑MREI͒ model, Chang and Mitra 2 deduced their criteria in 1968. These criteria are for A x B 1−x C, m A , m B , m C are the atomic masses of atoms A, B, and C, and m A Ͻ m B . If m A Ͻ BC ͓ BC = m B m C / ͑m B + m C ͒ is the reduced mass of atoms B and C͔, it exhibits two-mode behavior; whereas the opposite is true for the one-mode behavior. These criteria succeed in interpreting many experimental results, such as the two-mode behavior for longitudinal optical ͑LO͒ phonons in AlGaAs ͑Ref. 3͒ and AlInAs ͑Ref. 4͒ and the one-mode behavior for A 1 ͑LO͒ in hexagonal MgZnO. 5 For III-nitride alloys, the most extensively studied one is AlGaN. Raman scattering has shown that E 2 H phonon shows two-mode behavior and A 1 ͑LO͒ shows one-mode behavior. 6 The one-mode behavior for longitudinal phonons A 1 ͑LO͒ is in good agreement with the one-mode criteria of Chang and Mitra, 2 i.e., m Al Ͼ GaN , because of the much smaller mass of nitrogen atom than Al and Ga atom. Those observations have stimulated a lot of theoretical research to interpret the experimental results of AlGaN and predict the future results of other III-nitride alloy, including AlInN, for which one-mode criteria m Al Ͼ InN are still satisfied well. They have usually adopted various versions of MREI model as theoretical basis. 7,8 For example, Grille et al. 7 predicted that for AlInN, A 1 ͑LO͒ also exhibits one-mode behavior and E 2 H exhibits two-mode behavior.Naik et al. 9 used Raman scattering ...

show abstract

Section: Whenmentioning

confidence: 99%

“…4͒ and the one-mode behavior for A 1 ͑LO͒ in hexagonal MgZnO. 5 For III-nitride alloys, the most extensively studied one is AlGaN. Raman scattering has shown that E 2 H phonon shows two-mode behavior and A 1 ͑LO͒ shows one-mode behavior.…”

mentioning

confidence: 99%

Raman scattering of indium-richAlxIn1−xN: Unexpected two-mode behavior of
Kang
¹
,
Hashimoto
²
,
Yamamoto
³

2009
Phys. Rev. B
24
3
10
0
View full text Add to dashboard Cite

show abstract

“…Raman scattering is an important way for examining the strain, composition, long-range order and local structure in alloy layers. However, little information on phonons is reported in literatures on Mg x Zn 1-x O alloys [7][8][9]. In this paper, we report the Raman spectra from the Mg x Zn 1-x O alloys with hexagonal structures.…”

mentioning

confidence: 94%

Raman spectra and phonon modes of Mg_xZn_1–xO alloy films

Wei

Shen

et al. 2006

Phys. Status Solidi (c)

View full text Add to dashboard Cite

Hexagonal Mg x Zn 1-x O alloy layers with 0 ≤ x < 0.3 have been grown by plasma-assisted molecular beam epitaxy on sapphire (006) and Si (111) substrates. Their crystal structures are characterized by x-ray diffraction spectroscopy. The nonresonant and resonant Raman spectra were measured using 488 nm line from Ar + laser, and 325 nm line from He-Cd laser by backscattering geometry. Four Raman modes (E 2 high , LO, TO, multiphonon processes) were observed in the nonresonant Raman spectra of hexagonal Mg x Zn 1-x O with different Mg contents. The optical phonon frequencies were found to display one-mode behaviour for all the samples since no separate ZnO-and MgO-like modes were observed. The longwavelength frequencies of ZnO-like optical phonons measured in the resonant Raman spectra can be expressed as linear functions of x. These behaviours can be explained within a modified random-elementisodisplacement model (MREI).

show abstract

“…The structural differences existing between the two end points of the ZnMgO solid solution lead to the existence of different crystalline structures for the solutions with Zn-rich and Mg-rich compositions, corresponding to the wurtzite and rocksalt structures, respectively. This is also accompanied by an intermediate region -corresponding to values of the relative Mg content in the range 0.33 < Mg/(Mg + Zn) < 0.45 for samples grown by reactive electron beam evaporation 18, 19 and in the range 0.42 < Mg/(Mg + Zn) < 0.64 for samples grown by magnetron sputtering 20 - that is characterized by the existence of a mixed phase. For photovoltaic applications, the range of compositions is confined within the Zn-rich region with 0 < Mg/(Mg + Zn) < 0.33 21, 22 , where the ZnMgO solid solution has a wurtzite structure.…”

Section: Introductionmentioning

confidence: 95%

Resonant Raman scattering based approaches for the quantitative assessment of nanometric ZnMgO layers in high efficiency chalcogenide solar cells

Guc

Hariskos

Calvo‐Barrio

et al. 2017

Sci Rep

View full text Add to dashboard Cite

This work reports a detailed resonant Raman scattering analysis of ZnMgO solid solution nanometric layers that are being developed for high efficiency chalcogenide solar cells. This includes layers with thicknesses below 100 nm and compositions corresponding to Zn/(Zn + Mg) content rations in the range between 0% and 30%. The vibrational characterization of the layers grown with different compositions and thicknesses has allowed deepening in the knowledge of the sensitivity of the different Raman spectral features on the characteristics of the layers, corroborating the viability of resonant Raman scattering based techniques for their non-destructive quantitative assessment. This has included a deeper analysis of different experimental approaches for the quantitative assessment of the layer thickness, based on (a) the analysis of the intensity of the ZnMgO main Raman peak; (b) the evaluation of the changes of the intensity of the main Raman peak from the subjacent layer located below the ZnMgO one; and (c) the study of the changes in the relative intensity of the first to second/third order ZnMgO peaks. In all these cases, the implications related to the presence of quantum confinement effects in the nanocrystalline layers grown with different thicknesses have been discussed and evaluated.

show abstract

Long-wavelength optical phonon properties of ternary MgZnO thin films

Cited by 43 publications

References 13 publications

Raman scattering of indium-richAlxIn1−xN: Unexpected two-mode behavior of
Kang
¹
,
Hashimoto
²
,
Yamamoto
³

2009
Phys. Rev. B
24
3
10
0
View full text Add to dashboard Cite

Raman scattering of indium-richAlxIn1−xN: Unexpected two-mode behavior of
Kang
¹
,
Hashimoto
²
,
Yamamoto
³

2009
Phys. Rev. B
24
3
10
0
View full text Add to dashboard Cite

Raman spectra and phonon modes of Mg_xZn_1–xO alloy films

Resonant Raman scattering based approaches for the quantitative assessment of nanometric ZnMgO layers in high efficiency chalcogenide solar cells

Contact Info

Product

Resources

About

Long-wavelength optical phonon properties of ternary MgZnO thin films

Cited by 43 publications

References 13 publications

Raman scattering of indium-richAlxIn1−xN: Unexpected two-mode behavior ofKang1, Hashimoto2, Yamamoto3 2009Phys. Rev. B243100View full textAdd to dashboardCite

Raman scattering of indium-richAlxIn1−xN: Unexpected two-mode behavior ofKang1, Hashimoto2, Yamamoto3 2009Phys. Rev. B243100View full textAdd to dashboardCite

Raman spectra and phonon modes of MgxZn1–xO alloy films

Resonant Raman scattering based approaches for the quantitative assessment of nanometric ZnMgO layers in high efficiency chalcogenide solar cells

Contact Info

Product

Resources

About

Raman scattering of indium-richAlxIn1−xN: Unexpected two-mode behavior of
Kang
¹
,
Hashimoto
²
,
Yamamoto
³

2009
Phys. Rev. B
24
3
10
0
View full text Add to dashboard Cite

Raman scattering of indium-richAlxIn1−xN: Unexpected two-mode behavior of
Kang
¹
,
Hashimoto
²
,
Yamamoto
³

2009
Phys. Rev. B
24
3
10
0
View full text Add to dashboard Cite

Raman spectra and phonon modes of Mg_xZn_1–xO alloy films