The formation of Al{sub 2}O{sub 3}/V{sub 2}O{sub 3} multilayer structures by high-dose ion implantation

High-resolution TEM, RBS-channeling and x-ray-diffraction techniques have been used to characterize multilayered structures formed by the high-dose co-implantation of vanadium and oxygen into single crystals of {alpha}-Al{sub 2}O{sub 3}. Thin, two-dimensional multilayered structures have been formed by implanting c-axis and a-axis-oriented single crystals of Al{sub 2}O{sub 3} at room temperature with vanadium (10{sup 17} ions/cm{sup 2} at 300 keV) and oxygen (2 x 10{sup 17} ions/cm{sup 2}, 120 keV) followed by a rapid anneal at 1,000 C. Cross-sectional TEM studies showed that this process produced a buried layer of V{sub 2}O{sub 3} located about 120 nm below the Al{sub 2}O{sub 3} surface. X-ray-diffraction investigations revealed that this layer is epitaxially oriented in three dimensions with respect to the host Al{sub 2}O{sub 3} lattice. The orientational relationship was subsequently confirmed by RBS/channeling techniques. V{sub 2}O{sub 3} exhibits a first-order phase transition at about 155 K that is accompanied by striking changes in its electrical and optical properties, and this phase transition was observed through in-situ TEM cooling studies of cross-sectional samples