Electrical conductivity of passivated Si2Te3 single crystals

Bauer, Hugues; Birkholz, U.

doi:10.1002/pssa.2210490114

Cited by 5 publications

(2 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Semiconducting Si 2 Te 3 nanostructures have recently emerged as materials that have potential applications as silicon-based devices because of their unprecedented structural variabilities [1][2][3][4][5][6][7][8] . Previous studies of the electrical and optical properties of bulk Si 2 Te 3 trace back to more than 50 years ago [9][10][11][12][13][14][15] . The p-type Si 2 Te 3 semiconductor was reported to have both direct and indirect bandgap structures 9 with a hexagonal close-packed Te sublattice and Si atoms entangled as the Si-Si dimer between the Te layers 10 .…”

mentioning

confidence: 97%

Anisotropic optical properties of single Si2Te3 nanoplates

Chen

Bhattarai

Cui

et al. 2020

Sci Rep

View full text Add to dashboard Cite

We report a combined experimental and computational study of the optical properties of individual silicon telluride (Si2Te3) nanoplates. The p-type semiconductor Si2Te3 has a unique layered crystal structure with hexagonal closed-packed Te sublattices and Si–Si dimers occupying octahedral intercalation sites. The orientation of the silicon dimers leads to unique optical and electronic properties. Two-dimensional Si2Te3 nanoplates with thicknesses of hundreds of nanometers and lateral sizes of tens of micrometers are synthesized by a chemical vapor deposition technique. At temperatures below 150 K, the Si2Te3 nanoplates exhibit a direct band structure with a band gap energy of 2.394 eV at 7 K and an estimated free exciton binding energy of 150 meV. Polarized reflection measurements at different temperatures show anisotropy in the absorption coefficient due to an anisotropic orientation of the silicon dimers, which is in excellent agreement with theoretical calculations of the dielectric functions. Polarized Raman measurements of single Si2Te3 nanoplates at different temperatures reveal various vibrational modes, which agree with density functional perturbation theory calculations. The unique structural and optical properties of nanostructured Si2Te3 hold great potential applications in optoelectronics and chemical sensing.

show abstract

mentioning

confidence: 97%

Anisotropic optical properties of single Si2Te3 nanoplates

Chen

Bhattarai

Cui

et al. 2020

Sci Rep

View full text Add to dashboard Cite

show abstract

“…The nature of chemical bonds, physical and physical-chemical properties of crystals are largely defined by their composition, crystalline and energy structure, as well as the charge of valence electrons distribution. Despite the numerous studies of crystalline structure [1,2], electrical conductivity, Zeebek coefficient [11][12][13][14], reflection and fundamental absorption spectra [15,16], photoconductivity [17,18], photoluminescence [7,18,19] and vibrational spectra [20] of Si 2 Te 3 crystals, the study of their band structure is not numerous [21,22]. The first results of calculations aimed at the Si 2 Te 3 crystal electronic structure performed by the density functional method in the local density approximation (LDA) are given in [21].…”

Section: Introductionmentioning

confidence: 99%

Electronic structure, optical and photoelectrical properties of crystalline Si2Te3

Блецкан¹

2019

Semicond. phys., quantum electron. optoelectron.

View full text Add to dashboard Cite

In the framework of the density functional theory (DFT) in the approximation of local density adjusted for the strong correlation (LDA+U method), calculated were the band structure, total and partial densities of electronic states, as well as the spatial distribution of the electron density. According to the results of the calculation, Si 2 Te 3 is an indirect-gap semiconductor with the calculated band gap calc gi E = 2.05 eV, close to the experimentally measured opt g E = 2.13 eV. The absorption edge and photoconductivity spectra of Si 2 Te 3 crystal within the temperature range 80...293 K have been measured. It has been shown that the dependence of the absorption coefficient on the photon energy is described by the Urbach rule. The parameter σ 0 , associated with the constant of electron-phonon interaction, and the energy of effective phonons ħω ph , involved in formation of the absorption edge of crystalline Si 2 Te 3 , were determined using the temperature dependence of the absorption edge slope. Deviation from the stoichiometric composition in the direction of excess tellurium significantly affects the spectral distribution of the photoconductivity of Si 2 Te 3 crystals.

show abstract

Anisotropy of electrical conductivity in Si2Te3

Rick¹,

Rosenzweig²,

Birkholz³

1984

Phys. Stat. Sol. (a)

View full text Add to dashboard Cite

Silicon telluride Si T e is a p-type semiconductor with hexagonal layer structure and space group p3ml /1, 2/. The crystallographic c-axis is perpendicular to the layers. The crystals a r e strongly hygroscopic and even t r a c e s of water vapour cause a chemical reaction. A s a result Si02 and free tellurium are deposited on the sample surface /3, 4/. F o r electrical measurements on high resistivity Si2Te3 it is necessary to avoid this reaction o r to restore the original low conductivity of the surface. 5In a previous investigation /5, 6/ the samples were cleaved in high vacuum before the evaporation of gold contacts. During the transfer to the measurement apparatus, however, the samples were exposed to the laboratory atmosphere. Therefore the surface reaction produced a tellurium film, which was removed by a vacuum heat treatment a t 520 K. The reproducibility of the experimental results was not satisfactory.In this note we used an ultra-high vacuum equipment to avoid chemical surface reactions. In this apparatus it was possible to clean the samples, to apply gold contacts by evaporation, and to perform measurements of the electrical conductivity under permanent vacuum conditions. T o obtain clean sample surfaces we cleaved the samples with the help of an adhesive tape o r sputtered the crystal surfaces with an argon ion beam. With the first method, however, it was not possible to obtain two parallel sample surfaces perpendicular to the c-axis as good cleavage planes. Therefore the measurement of the electrical conductivity parallel t o the c-axis was only feasible with sputtered samples. The crystals were grown by transport in the vapour phase /2, 7/. The samples were platelets of 70 to 100 p m thickness and 40 t o 50 m m a r e a . The sputtering was performed at an argon p r e s s u r e of 1 0 2 -4 mbar, the typical 1 ) Kaiserstr. 12, D-7500 Karlsruhe, FFG.

show abstract

Electrical conductivity of passivated Si2Te3 single crystals

Cited by 5 publications

References 5 publications

Anisotropic optical properties of single Si2Te3 nanoplates

Anisotropic optical properties of single Si2Te3 nanoplates

Electronic structure, optical and photoelectrical properties of crystalline Si2Te3

Anisotropy of electrical conductivity in Si2Te3

Contact Info

Product

Resources

About