| 1. |
|
|
| 2. |
- Mühlbacher, Marlene, 1987-, et al.
(författare)
-
Cu diffusion in single-crystal and polycrystalline TiN barrier layers : A high-resolution experimental study supported by first-principles calculations
- 2015
-
Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 118:8
-
Tidskriftsartikel (refereegranskat)abstract
- Dense single-crystal and polycrystalline TiN/Cu stacks were prepared by unbalanced DC magnetron sputter deposition at a substrate temperature of 700 °C and a pulsed bias potential of -100 V. The microstructural variation was achieved by using two different substrate materials, MgO(001) and thermally oxidized Si(001), respectively. Subsequently, the stacks were subjected to isothermal annealing treatments at 900 °C for 1 h in high vacuum to induce the diffusion of Cu into the TiN. The performance of the TiN diffusion barrier layers was evaluated by cross-sectional transmission electron microscopy in combination with energy-dispersive X-ray spectrometry mapping and atom probe tomography. No Cu penetration was evident in the single-crystal stack up to annealing temperatures of 900 °C, due to the low density of line and planar defects in single-crystal TiN. However, at higher annealing temperatures when diffusion becomes more prominent, density-functional theory calculations predict a stoichiometry-dependent atomic diffusion mechanism of Cu in bulk TiN, with Cu diffusing on the N sublattice for the experimental N/Ti ratio. In comparison, localized diffusion of Cu along grain boundaries in the columnar polycrystalline TiN barriers was detected after the annealing treatment. The maximum observed diffusion length was approximately 30 nm, yielding a grain boundary diffusion coefficient of the order of 10‑16 cm2s-1 at 900 °C. This is 10 to 100 times less than for comparable underdense polycrystalline TiN coatings deposited without external substrate heating or bias potential. The combined numerical and experimental approach presented in this paper enables the contrasting juxtaposition of diffusion phenomena and mechanisms in two TiN coatings, which differ from each other only in the presence of grain boundaries.
|
|
| 3. |
|
|
| 4. |
- Schalk, Oliver, et al.
(författare)
-
Internal Conversion versus Intersystem Crossing : What Drives the Gas Phase Dynamics of Cyclic alpha,beta-Enones?
- 2014
-
Ingår i: Journal of Physical Chemistry A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 118:12, s. 2279-2287
-
Tidskriftsartikel (refereegranskat)abstract
- We investigate the competition between intersystem crossing (ISC) and internal conversion (IC) as nonradiative relaxation pathways in cyclic alpha,beta-unsaturated enones following excitation to their lowest lying (1)pi pi* state, by means of time-resolved photoelectron spectroscopy and ab initio computation. Upon excitation, the (1)pi pi* state of 2-cyclopentenone decays to the lowest lying (1)pi pi* state within 120 +/- 20 fs. Within 1.2 +/- 0.2 ps, the molecule subsequently decays to the triplet manifold and the singlet ground state, with quantum yields of 0.35 and 0.65, respectively. The corresponding dynamics in modified derivatives, obtained by selective methylation, show a decrease in both IC and ISC rates, with the quantum yields of ISC varying between 0.35 and 0.08. The rapid rates of ISC are explained by a large spin orbit coupling of 45-60 cm(-1) over an extended region of near degeneracy between the singlet and triplet state. Furthermore, the rate of IC is depressed by the existence of a well-defined minimum on the (1)n pi* potential energy surface. The nonadiabatic pathways evinced by the present results highlight the fact that these molecular systems conceptually represent "intermediate cases" between ultrafast dynamics mediated by vibrational motions at conical intersections versus those by statistical decay mechanisms.
|
|
| 5. |
- Schalk, Peter
(författare)
-
Acknowledgement
- 2002
-
Ingår i: Buddhism among Tamils in Pre-Colonial Tamilakam and Ilam. Prologue. The Pre-Pallava and the Pallava Period. - : AUU. ; , s. 11-14
-
Bokkapitel (refereegranskat)
|
|
| 6. |
- Schalk, Peter, 1944-
(författare)
-
Bekehrung als Vollendung im Hinduismus
- 2010
-
Ingår i: Interreligiöse Verständigung zu Glaubensverbreitung und Religionswechsel. - Berlin : EB-Verlag Dr Brandt. - 978 3 936912 91 3 ; , s. 167-196
-
Bokkapitel (refereegranskat)
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
|
|
