Characterization of ZnSe Nanolayers by Spectroscopic Ellipsometry

• Authors: M. Šćepanović , M. Grujić-Brojčin , D. Nesheva , Z. Levi , I. Bineva , Z. Popović
• Languages of publication: EN

Abstracts

EN

Single layers of ZnSe with thicknesses of 30, 40, 50, 70 and 100 nm are deposited at room substrate temperature by thermal evaporation of ZnSe powder in vacuum. The layers surface morphology has been investigated by atomic force microscopy. Structural characterization by the Raman scattering measurement revealed the existence of randomly oriented crystalline ZnSe particles in all layers, and the presence of amorphous phase in layers thinner than 100 nm. The ellipsometric measurements were performed in the range from 1.5 to 5 eV at room temperature in air. To interpret the experimental results, the Bruggeman effective medium approximation of dielectric function of ZnSe layers has been used, representing the layers as different mixtures of crystalline ZnSe (c-ZnSe), amorphous ZnSe (a-ZnSe), and voids. The assumption of polycrystalline ZnSe layers modeled as mixture of porous c-ZnSe (with volume fraction of voids ≈ 0.17) and a-ZnSe gives the best fit of ellipsometric experimental data. Single layer thicknesses similar to those expected from preparation conditions have been obtained by this fitting procedure. It has been also found that decrease in the layer thickness causes an increase of the volume fraction of a-ZnSe. Thus, c-ZnSe/a-ZnSe ratio, porosity and layer thickness obtained by spectroscopic ellipsometry, provides useful information about crystallinity and micro-/nanostructure of ZnSe nanolayers.

Keywords

EN

81.07.-b; 81.15.-z; 81.05.Dz; 78.30.-j; 07.60.Fs; 68.55.-a

Discipline

• 81.07.-b: Nanoscale materials and structures: fabrication and characterization(for structure of nanoscale materials, see 61.46.-w; for nanostructured materials in electrochemistry, see 82.45.Yz; see also 62.23.-c Structural classes of nanoscale systems in mechanical properties of condensed matter)
• 07.60.Fs: Polarimeters and ellipsometers
• 81.05.Dz: II-VI semiconductors
• 78.30.-j: Infrared and Raman spectra(for vibrational states in crystals and disordered systems, see 63.20.-e and 63.50.-x, respectively; for Raman spectra of superconductors, see 74.25.nd)
• 81.15.-z: Methods of deposition of films and coatings; film growth and epitaxy(for structure of thin films, see 68.55.-a; see also 85.40.Sz Deposition technology in microelectronics; for epitaxial dielectric films, see 77.55.Px)
• 68.55.-a: Thin film structure and morphology(for methods of thin film deposition, film growth and epitaxy, see 81.15.-z)

• Publisher: Institute of Physics, Polish Academy of Sciences
• Journal: Acta Physica Polonica A
• Year: 2009
• Volume: 116
• Issue: 4
• Pages: 708-711

Dates

published

2009-10

Contributors

author

M. Šćepanović

• Center for Solid State Physics and New Materials, Institute of Physics, Belgrade, Serbia

author

M. Grujić-Brojčin

• Center for Solid State Physics and New Materials, Institute of Physics, Belgrade, Serbia

author

D. Nesheva

• Institute of Solid State Physics, Bulgarian Academy of Sciences, Sofia, Bulgaria

author

Z. Levi

• Institute of Solid State Physics, Bulgarian Academy of Sciences, Sofia, Bulgaria

author

I. Bineva

• Institute of Solid State Physics, Bulgarian Academy of Sciences, Sofia, Bulgaria

author

Z. Popović

• Center for Solid State Physics and New Materials, Institute of Physics, Belgrade, Serbia

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Identifiers

DOI

10.12693/APhysPolA.116.708