Hexagonal germanium formed via a pressure-induced phase transformation of amorphous germanium under controlled nanoindentation
| Autor: | Marvin L. Cohen, Jodie Bradby, Sarita Deshmukh, James Williams, Brad D. Malone, Brett C. Johnson, Bianca Haber |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
Phase transition
Materials science Analytical chemistry chemistry.chemical_element Diamond Germanium Nanoindentation engineering.material Condensed Matter Physics symbols.namesake Crystallography chemistry Phase (matter) symbols engineering General Materials Science Diamond cubic Selected area diffraction Raman spectroscopy |
| Zdroj: | physica status solidi (RRL) - Rapid Research Letters. 7:355-359 |
| ISSN: | 1862-6254 |
| Popis: | We have studied the stable end phase formed in amorphous germanium (a-Ge) films that have been subjected to a pressure-induced phase transformation under indentation loading using a large (20 µm) spherical indenter. After indentation the samples have been annealed at room temperature to remove any residual unstable R8 and BC8 phases. Raman spectroscopy indicates a single broad peak centred around 292 cm–1 and we have used first principles density functional perturbation theory calculations and simulated Raman spectra for nano-crystalline diamond cubic germanium (DC-Ge) to help identification of the final phase as hexagonal diamond germanium (HEX-Ge). Transmission electron microscopy and selected area diffraction analysis confirmed the presence of a dominant HEX-Ge end phase. These results help explain significant inconsistencies in the literature relating to indentation-induced phase transitions in DC- and a-Ge. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Plný text