Published in Mater. Res. Soc. Symp. Proc. Vol. 1108, A09-32 (2009).
Nucleation and Stoichiometry Dependence of rutile-TiO2(001)/GaN(0001) Thin Films Grown by Plasma-Assisted Molecular Beam Epitaxy
Costel Constantin,1 Kai Sun,2 R. M. Feenstra3
1Seton Hall University, 400 South Orange Ave, South Orange, NJ 07079
2University of Michigan, Ann Arbor, Michigan 48109-2143
3Dept. Physics, Carnegie Mellon University, Pittsburgh, PA 15213
In this work we explore both the initial nucleation and the stoichiometry of rutile-TiO2(001) grown on wurtzite GaN(0001) by radio-frequency O2-plasma molecular beam epitaxy. Two studies are performed; in the first, the dependence of the growth on stoichiometry (Ti-rich and O-rich) is observed using reflection high energy electron diffraction and high resolution transmission electron microscopy. In the second study we examine the effect of different initial nucleation surfaces (i.e. Ga-terminated and excess Ga-terminated) and compare the interfaces and bulk crystallinity of the TiO2(001) films grown on top of these surfaces. High-resolution transmission electron microscopy and x-ray diffraction measurements show a better interface for TiO2(001)/Ga-terminated - GaN(0001) as compared to the TiO2(001)/excess Ga-terminated - GaN(0001).
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