Abstract
The local environments of Sc and Y in predominantly ⟨002⟩ textured, Al1-xDoxN (Do = Sc, x = 0.25, 0.30 or Y, x = 0.25) sputtered thin films with wurtzite symmetry were investigated using X-ray absorption (XAS) and photoelectron (XPS) spectroscopies. We present evidence from the X-ray absorption fine structure (XAFS) spectra that, when x = 0.25, both Sc3+ and Y3+ ions are able to substitute for Al3+, thereby acquiring four tetrahedrally coordinated nitrogen ligands, i.e., coordination number (CN) of 4. On this basis, the crystal radius of the dopant species in the wurtzite lattice, not available heretofore, could be calculated. By modeling the scandium local environment, extended XAFS (EXAFS) analysis suggests that when x increases from 0.25 to 0.30, CN for a fraction of the Sc ions increases from 4 to 6, signaling octahedral coordination. This change occurs at a dopant concentration significantly lower than the reported maximum concentration of Sc (42 mol % Sc) in wurtzite (Al, Sc)N. XPS spectra provide support for our observation that the local environment of Sc in (Al, Sc)N may include more than one type of coordination.
| Original language | English |
|---|---|
| Pages (from-to) | 853-861 |
| Number of pages | 9 |
| Journal | ACS Applied Electronic Materials |
| Volume | 6 |
| Issue number | 2 |
| DOIs | |
| State | Published - 27 Feb 2024 |
| Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2024 The Authors. Published by American Chemical Society
Funding
X-ray absorption spectroscopy studies and data analysis by A.I.F. were supported by NSF Grant number DMR-2312690. I.L. acknowledges the BSF program grant 2022786 for his contribution to the XAS studies. These grants are the two parts of the NSF-BSF grant awarded to A.I.F. and I.L., respectively. This research used beamlines 7-BM and 8-BM of the National Synchrotron Light Source II (NSLS-II), a U.S. DOE Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under contract no. DE-SC0012704. The authors acknowledge support by the Synchrotron Catalysis Consortium funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Grant No. DE-SC0012335. A.I.F. acknowledges support by a Weston Visiting Professorship during his stay at the Weizmann Institute of Science. This work is made possible in part by the historic generosity of the Harold Perlman Family. X-ray absorption spectroscopy studies and data analysis by A.I.F. were supported by NSF Grant number DMR-2312690. I.L. acknowledges the BSF program grant 2022786 for his contribution to the XAS studies. These grants are the two parts of the NSF-BSF grant awarded to A.I.F. and I.L., respectively. This research used beamlines 7-BM and 8-BM of the National Synchrotron Light Source II (NSLS-II), a U.S. DOE Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under contract no. DE-SC0012704. The authors acknowledge support by the Synchrotron Catalysis Consortium funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Grant No. DE-SC0012335. A.I.F. acknowledges support by a Weston Visiting Professorship during his stay at the Weizmann Institute of Science. This work is made possible in part by the historic generosity of the Harold Perlman Family.
| Funders | Funder number |
|---|---|
| NSF-BSF | |
| Synchrotron Catalysis Consortium | |
| National Science Foundation | DMR-2312690 |
| U.S. Department of Energy | |
| Office of Science | |
| Basic Energy Sciences | DE-SC0012335 |
| Brookhaven National Laboratory | DE-SC0012704 |
| United States-Israel Binational Science Foundation | 2022786 |
Keywords
- aluminum scandium nitride
- aluminum yttrium nitride
- piezoelectric
- seeding layer
- sputtering
- texture