The formation of Al2O3/V2O3 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 α-Al2O3. Thin, two-dimensional multilayered structures have been formed by implanting c-axis and a-axis-oriented single crystals of Al2O3 at room temperature with vanadium (1017 ions/cm2 at 300 keV) and oxygen (2 x 1017 ions/cm2, 120 keV) followed by a rapid anneal at 1,000 C. Cross-sectional TEM studies showed that this process produced a buried layer of V2O3 located about 120 nm below the Al2O3 surface. X-ray-diffraction investigations revealed that this layer is epitaxially oriented in three dimensions with respect to the host Al2O3 lattice. The orientational relationship was subsequently confirmed by RBS/channeling techniques. V2O3 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