Morphology and Optical Properties of Thin Cd3As2 Films of a Dirac Semimetal Compound
| Autor: | Dagmar Chvostova, N. N. Kovaleva, Ladislav Fekete, Andrei Muratov |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
inorganic chemicals
lcsh:TN1-997 Materials science FOS: Physical sciences Cadmium arsenide macromolecular substances 02 engineering and technology 01 natural sciences spectroscopic ellipsometry Tetragonal crystal system chemistry.chemical_compound Condensed Matter - Strongly Correlated Electrons 0103 physical sciences General Materials Science Physics::Atomic Physics Thin film 010306 general physics Electronic band structure lcsh:Mining engineering. Metallurgy Condensed Matter - Materials Science atomic force microscopy Strongly Correlated Electrons (cond-mat.str-el) Condensed matter physics Dirac semimetals Doping technology industry and agriculture Metals and Alloys Materials Science (cond-mat.mtrl-sci) Sputter deposition 021001 nanoscience & nanotechnology diagnosis Semimetal TheoryofComputation_MATHEMATICALLOGICANDFORMALLANGUAGES cadmium arsenide Absorption edge chemistry thin films biological sciences Condensed Matter::Strongly Correlated Electrons High Energy Physics::Experiment 0210 nano-technology |
| Zdroj: | Metals, Vol 10, Iss 1398, p 1398 (2020) Metals Volume 10 Issue 10 |
| ISSN: | 2075-4701 |
| Popis: | Using atomic-force microscopy (AFM) and wide-band (0.02&ndash 8.5 eV) spectroscopic ellipsometry techniques, we investigated the morphology and optical properties of Cd3As2 films grown by non-reactive RF magnetron sputtering on two types of oriented crystalline substrates (100)p-Si and (001) &alpha Al2O3. The AFM study revealed the grainy morphology of the films due to island incorporation during the film growth. The complex dielectric function spectra of the annealed Cd3As2/Al2O3 films manifest pronounced interband optical transitions at 1.2 and 3.0 eV, in excellent agreement with the theoretical calculations for the body centered tetragonal Cd3As2 crystal structure. We discovered that due to electronic excitations to the Cd(s) conical bands, the low-energy absorption edge of the annealed Cd3As2 films reveals a linear dependence. We found that for the annealed Cd3As2 films, the Cd(s) conical node may be shifted in energy by about 0.08&ndash 0.18 eV above the heavy-flat As(p) valence band, determining the optical gap value. The as-grown Cd3As2 films exhibit the pronounced changes of the electronic band structure due to the doping effect associated with Cd non-stoichiometry, where fine-tuning of the Cd concentration may result in the gapless electronic band structure of Dirac semimetals. |
| Databáze: | OpenAIRE |
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