Raman spectra and phonon modes of Mg_xZn_1–xO alloy films

Abstract

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).

Synthesis and characterization of well-aligned Zn1−xMgxO nanorods and film by metal organic chemical vapor deposition

“…One is that the intensities of A 1 (TO) and E 2 high both are slightly reduced when the content of Mg increases, and the other is that the $330, $1068 and $1155 cm -1 peaks of samples 2-4 corresponding to multiple-phonon scattering become weak and broad, the intensities of all observed vibrational modes decrease and their line shapes become more asymmetric, which are attributed to the incorporation of Mg. However, the peaks do not show a significant shift compared with pure ZnO and no new Raman peaks appear in our samples 2-4 [28,29]. Fig.…”

Combinatorial growth of Mgx Zn1–xO epilayers by chemical vapor deposition

“…5 by the drawn line. In the small composition range investigated (x < 0.1) the shift is almost linear as found by Wei et al [10] and Bundesmann et al [7].…”

“…To evaluate the Mg compositions in the films we conducted Raman experiments [7][8][9][10] and determined the frequency of the longitudinal optical (LO) phonon in…”

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

“…The figure includes also data previously reported in the literature 28, 30 , together with those derived from the analysis of the spectra shown in Fig. 3.…”

“…Starts: experimental data from layers series (i). Circles: data reported from references 28, 30 . Full line shows the fitting of the data according to Equation 1. …”