Structural and resistance switching properties of epitaxial Pt/ZnO/TiN/Si(001) heterostructures

We report the bi-epitaxial growth of ZnO and resistance switching characteristics of Pt/ZnO/TiN-based heterojunction devices fabricated on Si(001) substrates by pulsed laser deposition. The structural properties of the heterostructures characterized by XRD (theta-2 theta, phi scans) and TEM confirm that the ZnO films having hexagonal wurtzite structure (six-fold symmetry) grow bi-epitaxially on the TiN buffer layer (four-fold symmetry). The Pt(111) grows epitaxially on ZnO(0001). The epitaxial relationship between the various films is given as (111)(Pt) parallel to (0001)(ZnO) parallel to (001)(TiN) parallel to (001)(Si) and [100](TiN) parallel to [100](Si), [2 (1) over bar(1) over bar0](ZnO) parallel to [110](TiN) or [10 (1) over bar0](ZnO) parallel to [110](TiN), and [10 (1) over bar](Pt) parallel to [2 (1) over bar(1) over bar0](ZnO). The effect of ZnO growth temperature on the electrical properties of Pt/ZnO/TiN devices is studied and correlated with the microstructure of the ZnO/TiN interface. The Pt/ZnO/TiN devices exhibited good bi-polar resistance switching characteristics at voltages as low as +/- 1V. (C) 2014 AIP Publishing LLC.