Spectroscopic studies of SiO<sub>x</sub>films irradiated with high energy electrons

Dzhurkov, V; Nesheva, D.; Šćepanović, M.; Nedev, N.; Kaschieva, S.; Dmitriev, S. N.; Popović, Zoran V.

doi:10.1088/1742-6596/558/1/012045

Cited by 10 publications

(5 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The positions of these peaks, which dominate the spectra for the thinnest samples, is fixed for all samples measured, and matches the peaks found in measurements of the substrate alone under the same measurement conditions. These substrate peaks match the ones reported by previous works in SiO 2 /Si: the one at 300 cm −1 is reported to be originated in the Si, and the one at 428 cm −1 has been reported to come from amorphous SiO 2 on SiO 2 /Si substrates [44,45]. As mentioned, the Raman signal for the thinnest samples is dominated by the substrate peaks, which almost overlap the weak E 1 2g and A 1g sample modes.…”

Section: Resultssupporting

confidence: 89%

Raman spectroscopy of few-layers TaS$_2$ and Mo-doped TaS$_2$ with enhanced superconductivity

Valencia-Ibáñez¹,

Jimenez-Guerrero²,

Salcedo-Pimienta³

et al. 2022

Preprint

View full text Add to dashboard Cite

The use of simple, fast and economic experimental tools to characterize low-dimensional materials is an important step in the process of democratizing the use of such materials in laboratories around the world. Raman spectroscopy has arisen as a way of indirectly determining the thickness of nanolayers of transition metal dichalcogenides (TMDs), avoiding the use of more expensive tools such as atomic force microscopy, and it is therefore a widely used technique in the study of semiconducting TMDs. However, the study of many metallic TMDs in the limit of few atomic layers is still behind when compared to their semiconducting counterparts, partly due to the lack of similar alternative characterization studies. In this work we present the characterization of the Raman spectrum, specifically of the E 1 2g -and A1g-modes, of mechanically exfoliated crystals of Ta1−xMoxS2 , a metallic TMD which exhibits charge density wave formation and superconductivity. The clear identification of contributions to the Raman spectrum coming from the SiO2/Si substrate, which overlap with the peaks coming from the sample, and which dominate in intensity in the few-layer-samples limit, allowed the isolation of the individual E 1 2g -and A1g-modes of the samples and, for the first time, the observation of a clear evolution of the Raman shifts of both modes as a function of sample thickness. The evolution of such peaks qualitatively resembles the evolution seen in other TMDs, and provide a way of indirectly determining sample thickness in the limit of few atomic layers at a low cost. In addition, we observe a softening (red-shift) of both E 1 2g -and A1g-modes with Mo-doping in the nanolayers, possibly related to the increased out-of-plane lattice parameter with respect to the pure compound.

show abstract

Section: Resultssupporting

confidence: 89%

Raman spectroscopy of few-layers TaS$_2$ and Mo-doped TaS$_2$ with enhanced superconductivity

Valencia-Ibáñez¹,

Jimenez-Guerrero²,

Salcedo-Pimienta³

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…These substrate peaks match the ones reported by previous works in SiO 2 /Si: the one at 300 cm −1 is reported to be originated in the Si, and the one at 428 cm −1 has been reported to come from amorphous SiO 2 on SiO 2 /Si substrates. [ 44,45 ] As mentioned, the Raman signal for the thinnest samples is dominated by the substrate peaks, which almost overlap the weak E

_{2{\rm{g}}}^1

and A 1g sample modes. The overlap between Raman modes frequencies for substrate and sample makes the analysis of the Raman spectrum of nanolayers of TaS 2 particularly challenging, in contrast with other dichalcogenides in which this effect is not as important.…”

Section: Resultsmentioning

confidence: 88%

Raman Spectroscopy of Few‐Layers TaS₂ and Mo‐Doped TaS₂ with Enhanced Superconductivity

Valencia‐Ibáñez

Jiménez-Guerrero

Salcedo‐Pimienta

et al. 2022

Adv Elect Materials

View full text Add to dashboard Cite

are strongly-bonded in the a-b plane but weakly-bonded and stacked by van der Waals forces in the c-direction, which gives them their low-dimensional character. [3][4][5][6][7] The weak van-der-Waals stacking of the planes allows the isolation of single-or few-atomic-layers-thick samples through relatively simple mechanical exfoliation techniques. [8,9] One of the most outstanding characteristics of this family of materials is that, depending on chemical composition, their electronic properties can range from band insulators to metals, and they can show exotic quantum phenomena such as charge density waves (CDWs), magnetic ordering, superconductivity, topological electronic states, among others. [4,10] Among all the members of this family of compounds, the semiconducting members are one the most studied materials in the last 2 decades. Their visible or near-visible range bandgaps, elevated electronic mobilities, large spin-orbit interaction, large susceptibility to changes in physical parameters, spatial scalability, among other characteristics, makes them ideal candidates for a large number of optoelectronics, spintronics, and electronics applications. [3,4,[11][12][13] Interestingly, all of these characteristics get enhanced or only appear in the limit of few atomic layers, and the body of literature characterizing electronic and physical properties in the monolayer limit is extensive. [14,15] The use of simple, fast, and economic experimental tools to characterize low-dimensional materials is an important step in the process of democratizing their use. Raman spectroscopy has arisen as a way of indirectly determining the thickness of nanolayers of transition metal dichalcogenides (TMDs), avoiding the use of more expensive tools such as atomic force microscopy, and it is therefore a widely used technique in the study of semiconducting TMDs. However, the study of many metallic TMDs in the limit of few atomic layers is still behind when compared to their semiconducting counterparts, partly due to the lack of similar alternative characterization studies. In this work the characterization of the Raman spectrum, specifically of the E 2 2g g 1 1 -and A 1g -modes, of mechanically exfoliated Ta 1−x Mo x S 2 , a metallic TMD which exhibits charge density wave (CDW) formation and superconductivity, is presented. The clear identification of contributions coming from the SiO 2 / Si substrate allowed the isolation of the individual E 2 2g g 1 1 -and A 1g -modes of the samples and, for the first time, the observation of a clear evolution of their Raman shifts as a function of sample thickness. This provides a way of indirectly determining sample thickness in the limit of few atomic layers in Ta 1−x Mo x S 2 .

show abstract

“…The corresponding surface morphologies are shown in Figure 5, while the element distributions of the non-treated and thermally treated samples are shown in Figure 6. The signals in the FTIR spectra include peaks at about 435 cm −1 , corresponding to Si-O bending; 515 cm −1 , for Si-O-Si bonds; 565 cm −1 , for Si-O-Si bending; 600-630 cm −1 , for Si-Si asymmetric vibrations [32]; 700, 740, and 780 cm −1 , for Si-O-Si symmetric stretching; 825 and 910 cm −1 , for Si-O asymmetric vibrations; 960 cm −1 , for Si-O-Si bonds [35]; and 1010 and 1110 cm −1 , attributed to Si-O-Si bonds [36][37][38].…”

Section: Resultsmentioning

confidence: 99%

Estimation of Thermal Stability of Si-SiO2-W Nanolayered Structures with Infrared Spectrometry

Avotina,

Goldmane,

Zaslavskis

et al. 2023

Materials

View full text Add to dashboard Cite

Nanolayered coatings are proposed for use in microelectronic devices where the size/performance ratio is becoming increasingly important, with the aim to achieve existing quality requirements while reducing the size of the devices and improving their ability to perform stably over multiple cycles. Si-SiO2-W structures have been proposed as a potential material for the fabrication of microelectronic devices. However, before such materials can be implemented in devices, their properties need to be carefully studied. In this study, Si-SiO2-W nanolayered structures were fabricated and subjected to numerous thermal treatment cycles at 150 °C. A total of 33 heating cycles were applied, resulting in a cumulative exposure of 264 h. The changes in chemical bonds and microstructure were monitored using Fourier Transform Infrared spectrometry (FTIR) and scanning electron microscopy (SEM). The FTIR signal at 960 cm−1, indicating the presence of W deposited on SiO2, was selected to characterize the thermal stability during the heating cycles. The estimated signal intensity variation closely resembled the normal inhomogeneity of the nanolayers. The increase in slope intensity was estimated to be 1.7 × 10−5.

show abstract

Spectroscopic studies of SiO_xfilms irradiated with high energy electrons

Cited by 10 publications

References 19 publications

Raman spectroscopy of few-layers TaS$_2$ and Mo-doped TaS$_2$ with enhanced superconductivity

Raman spectroscopy of few-layers TaS$_2$ and Mo-doped TaS$_2$ with enhanced superconductivity

Raman Spectroscopy of Few‐Layers TaS₂ and Mo‐Doped TaS₂ with Enhanced Superconductivity

Estimation of Thermal Stability of Si-SiO2-W Nanolayered Structures with Infrared Spectrometry

Contact Info

Product

Resources

About

Spectroscopic studies of SiOxfilms irradiated with high energy electrons

Cited by 10 publications

References 19 publications

Raman spectroscopy of few-layers TaS$_2$ and Mo-doped TaS$_2$ with enhanced superconductivity

Raman spectroscopy of few-layers TaS$_2$ and Mo-doped TaS$_2$ with enhanced superconductivity

Raman Spectroscopy of Few‐Layers TaS2 and Mo‐Doped TaS2 with Enhanced Superconductivity

Estimation of Thermal Stability of Si-SiO2-W Nanolayered Structures with Infrared Spectrometry

Contact Info

Product

Resources

About

Spectroscopic studies of SiO_xfilms irradiated with high energy electrons

Raman Spectroscopy of Few‐Layers TaS₂ and Mo‐Doped TaS₂ with Enhanced Superconductivity