Stripline as-75 nmr study of epitaxial iii-v semiconductor al0.5ga0.5as

We have carried out 75As NMR experiments on a single 5 μm thick epitaxial layer of metal organic chemical vapor deposition (MOCVD) AlxGa1–xAs, with x = 0.522, using a novel stripline based NMR setup. Different arsenic surroundings in the lattice give rise to five As[AlnGa4–n] sites with (n = 0–4). By mounting a thin film of Al0.522Ga0.478As in a home-built NMR probe with rotation stage and stripline detector, we could successfully distinguish different arsenic nearest neighbors coordinations. Furthermore, we were able to observe various 75As quadrupolar tensor orientations for each As[AlnGa4–n] coordination, which gives us a unique insight into the structure of this material. The individual resonances for each of these coordinations appear to be very broad, as a result of the variation in the local symmetry due to the distribution of aluminum and gallium over the lattice. In particular, the NMR resonance of one orientation of the As[Al2Ga2] site is strongly broadened. The line widths prove to be larger th...