Enhanced NMR with Optical Pumping Yields 75As Signals Selectively from a Buried GaAs Interface
| Autor: | Melanie A. Jenkins, Sophia E. Hayes, Zayd L. Ma, John F. Conley, Matthew M. Willmering |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
010302 applied physics
Chemistry Analytical chemistry Heterojunction 02 engineering and technology General Chemistry 021001 nanoscience & nanotechnology Laser 01 natural sciences Biochemistry Molecular physics Catalysis Thermal expansion law.invention Lattice mismatch Optical pumping Condensed Matter::Materials Science Atomic layer deposition Colloid and Surface Chemistry law Lattice (order) 0103 physical sciences 0210 nano-technology Aluminum oxide |
| Zdroj: | Journal of the American Chemical Society. 139:3930-3933 |
| ISSN: | 1520-5126 0002-7863 |
| DOI: | 10.1021/jacs.6b08970 |
| Popis: | We have measured the 75As signals arising from the interface region of single-crystal semi-insulating GaAs that has been coated and passivated with an aluminum oxide film deposited by atomic layer deposition (ALD) with optically pumped NMR (OPNMR). Using wavelength-selective optical pumping, the laser restricts the volume from which OPNMR signals are collected. Here, OPNMR signals were obtained from the interface region and distinguished from signals arising from the bulk. The interface region is highlighted by interactions that disrupt the cubic symmetry of the GaAs lattice, resulting in quadrupolar satellites for nuclear [Formula: see text] isotopes, whereas NMR of the "bulk" lattice is nominally unsplit. Quadrupolar splitting at the interface arises from strain based on lattice mismatch between the GaAs and ALD-deposited aluminum oxide due to their different coefficients of thermal expansion. Such spectroscopic evidence of strain can be useful for measuring lattice distortions at heterojunction boundaries and interfaces. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|