Step flow growth of Mn5Ge3 films on Ge(111) at room temperature

Petit, Matthieu; Boussadi, Amine; Heresanu, Vasile; Ranguis, Alain; Michez, Lisa

doi:10.1016/j.apsusc.2019.01.164

Cited by 8 publications

(7 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We believe that the film relaxation occurs via the formation of an array of interfacial dislocations. Such a lattice accommodation between Mn 5 Ge 3 and Ge(111) has been reported in previous works where the in-plane a-parameter appears partially 7,26,40 or fully 42 relaxed even for layers as thin as a few nanometers.…”

Section: A Microstructuresupporting

confidence: 81%

“…Similar results have been observed in polycrystalline sputtered 6 thin films and epitaxial structures grown by MBE using the low-temperature codeposition technique 7 . Note that in all cases, the c value is slightly lower than in the bulk material 37 , even for the pristine compound 16,28,40,41 , this feature being more pronounced in Mn 5 Ge 3 films grown by SPE. Interestingly, despite the 3.7 % in-plane lattice mismatch between Mn 5 Ge 3…”

Section: A Microstructurementioning

confidence: 80%

See 1 more Smart Citation

Unveiling the atomic position of C in Mn5Ge3Cx thin films

Michez

Petit

Heresanu

et al. 2022

Phys. Rev. Materials

Self Cite

View full text Add to dashboard Cite

Heavily carbon-doped Mn 5 Ge 3 is a unique compound for spintronics applications as it meets all the requirements for spin injection and detection in group-IV semiconductors. Despite the great improvement of the magnetic properties induced by C incorporation into Mn 5 Ge 3 compounds, very little information is available on its structural properties and the genuine role played by C atoms.In this paper, we have used a combination of advanced techniques to extensively characterize the structural and magnetic properties of Mn 5 Ge 3 C x films grown on Ge(111) by solid phase epitaxy as a function of C concentration. The increase of the Curie temperature induced by C doping up to 435 K is accompanied by a decrease of the out-of-plane c-lattice parameter. The Mn and C chemical environments and positions in the Mn 5 Ge 3 lattice have been thoroughly investigated usingx-ray absorption spectroscopy techniques (x-ray absorption near-edge structures and extended xray absorption fine structures) and scanning transmission electronic microscopy (STEM) combined to electron energy loss spectroscopy for the chemical analysis. The results have been systematically compared to a variety of structures that were identified as favorable in terms of formation energy by ab initio calculations. For x ≤ 0.5, the C atoms are mainly located in the octahedral voids formed by Mn atoms, which is confirmed by simulations and seen for the first time in real space by STEM. However, the latter reveals an inhomogeneous C incorporation, which is qualitatively correlated to the broad magnetic transition temperature. A higher C concentration leads to the formation of manganese carbide clusters that we identified as Mn 23 C 6 . Interestingly, other types of defects, such as interstitial Ge atoms, vacancies of Mn, and their association into line defects, have been detected. They take part in the strain relaxation process and are likely to be intimately related to the growth process. This paper provides a complete picture of the structure of Mn 5 Ge 3 C x in thin films grown by solid phase epitaxy, which is essential for optimizing their magnetic properties.

show abstract

Section: A Microstructuresupporting

confidence: 81%

Section: A Microstructurementioning

confidence: 80%

Unveiling the atomic position of C in Mn5Ge3Cx thin films

Michez

Petit

Heresanu

et al. 2022

Phys. Rev. Materials

Self Cite

View full text Add to dashboard Cite

show abstract

“…Furthermore, there was a tendency that films became flatter as the copper content increased. It was obvious that some parallel stripes were on most grains, as boxed in Figure d–l, which might be attributed to step flow growth of Cu x Ag 1– x I films . Especially in Figure j–l, enlarged parts of Figure g–i are shown, and step flow growth mode is marked with many parallel green lines, which indicate that such grains might grow from the same crystallographic plane of growth habituation.…”

Section: Resultsmentioning

confidence: 85%

“…It was obvious that some parallel stripes were on most grains, as boxed in Figure 4d−l, which might be attributed to step flow growth of Cu x Ag 1−x I films. 27 Especially in Figure 4j Considering that the thickness has a great influence on the optical properties of the film, SEM was used to characterize the cross section of the samples with x = 0.1−0.9, as shown in Figure 5. Cu 0.1 Ag 0.9 I and Cu 0.2 Ag 0.8 I show higher film thicknesses of 850.8 and 1014.0 nm, respectively, and many small grains of 100−500 nm grow in the vertical direction.…”

Section: Resultsmentioning

confidence: 99%

Significant Enhancement in Optoelectronic Properties of γ-Cu_xAg_1–xI Films Induced by Highly (111)-Preferred Orientation and Cu Content at Room Temperature

Dong

Zhao

Yan

et al. 2021

Crystal Growth & Design

View full text Add to dashboard Cite

Crystallographic orientations play a crucial part in optoelectronic properties of crystalline materials. This paper reported significant enhancement of optoelectronic properties in γ-phase copper silver iodide (γ-Cu x Ag 1−x I, 0.6 ≤ x ≤ 0.9) films compared with Cu-poor (0.1 ≤ x ≤ 0.4) counterparts due to highly (111)-preferred orientation and larger grains. Transient surface photovoltage spectroscopy reveals that Cu x Ag 1−x I (0.6 ≤ x ≤ 0.9) exhibits faster transferring rate and slower recombination rate of charge carriers than Cu-poor ones. The preferred orientation significantly influenced the photoelectric properties by reducing photocarrier recombination. In X-ray diffraction patterns and Rietveld results, it was displayed that Cu x Ag 1−x I (x = 0.1−0.9) films exhibit (111)-preferred orientation and higher crystallinity when Cu doping content increased. Scanning electron microscope electron channeling contrast imaging analysis demonstrated (111) with most grains with larger size in Cu-rich films compared with Cu-poor films that were grown in the step flow growth mode from (111)-preferred prisms defined as basic units. This paper may provide a valuable basis for Cu x Ag 1−x I with tunable band gaps, prepared via a simple route of a direct metal surface elemental reaction, applied in the hole transport layer or buffer layer in thin-film solar cells to achieve higher efficiencies.

show abstract

“…After the first report of ferromagnetism in the Ge 1 − x Mn x system with T C = ~116 K [16], the synthesis of Ge 1 − x Mn x DMSs has been the subject of numerous investigations [26][27][28][29][30][31][32][33][34][35][36]. Since it has been shown in Ref.…”

Section: Literature Review Of the Synthesis Of Ge 1 − X Mn X Dmsmentioning

confidence: 99%

Self-Assembly of GeMn Nanocolumns in GeMn Thin Films

Le¹

2020

Self-Assembly of Nanostructures and Patchy Nanoparticles

View full text Add to dashboard Cite

This chapter presents the results of growing GeMn nanocolumns on Ge(001) substrates by means of molecular beam epitaxy (MBE). The samples have been prepared by co-depositing Ge and Mn at growth temperature of 130°C and Mn at concentration of ~6% to ensure the reproduction of GeMn nanocolumns. Based on the observation of changes in reflection high-energy electron diffraction (RHEED) patterns during nanocolumn growth, surface signals of GeMn nanocolumn formation have been identified. Structural analysis using transmission electron microscopy (TEM) show the self-assembled nanocolumns with core-shell structure extend through the whole thickness of the GeMn layer. Most of nanocolumns are oriented perpendicular to the interface along the growth direction. The nanocolumn size has been determined to be about 5–8 nm in diameter and a maximum height of 80 nm. A phenomenological model has been proposed to explain the driving force for self-assembly and growth mechanisms of GeMn nanocolumns. The in-plane or lateral Mn diffusion/segregation is driven by a low solubility of Mn in Ge while the driving force of Mn vertical segregation is induced by the surfactant effect along the [001] direction.

show abstract

Step flow growth of Mn5Ge3 films on Ge(111) at room temperature

Cited by 8 publications

References 52 publications

Unveiling the atomic position of C in Mn5Ge3Cx thin films

Unveiling the atomic position of C in Mn5Ge3Cx thin films

Significant Enhancement in Optoelectronic Properties of γ-Cu_xAg_1–xI Films Induced by Highly (111)-Preferred Orientation and Cu Content at Room Temperature

Self-Assembly of GeMn Nanocolumns in GeMn Thin Films

Contact Info

Product

Resources

About

Step flow growth of Mn5Ge3 films on Ge(111) at room temperature

Cited by 8 publications

References 52 publications

Unveiling the atomic position of C in Mn5Ge3Cx thin films

Unveiling the atomic position of C in Mn5Ge3Cx thin films

Significant Enhancement in Optoelectronic Properties of γ-CuxAg1–xI Films Induced by Highly (111)-Preferred Orientation and Cu Content at Room Temperature

Self-Assembly of GeMn Nanocolumns in GeMn Thin Films

Contact Info

Product

Resources

About

Significant Enhancement in Optoelectronic Properties of γ-Cu_xAg_1–xI Films Induced by Highly (111)-Preferred Orientation and Cu Content at Room Temperature