Growth of highly conducting epitaxial ZnO–Pt–ZnO heterostructure on α-Al2O3 (0 0 0 1)

Here we report the growth of epitaxial ZnO–Pt–ZnO trilayer structures on sapphire (0 0 0 1) substrate by using pulsed laser deposition technique. These structures were characterized using X-ray diffraction, conventional and high-resolution transmission electron microscopy, STEM (scanning Transmission Electron microscopy-Atomic number) Z-contrast, optical transmittance and electrical resistivity measurements. X-ray diffraction and TEM experiments revealed the epitaxial nature of these structures, the orientation relationship being: 〈1 1 1〉pt||〈0 0 0 1〉ZnO||〈0 0 0 1〉〈0 0 0 1〉sapphire (out of plane) and 〈1 1 0〉pt||〈2 1¯ 1¯ 0〉ZnO||〈0 1 1¯ 0〉sapphire (in Plane) for the trilayer structure. Electrical and optical measurements showed that these heterostructures exhibit quite good electrical conductivity and at the same time possess moderate optical transmittance.