Thermal analysis of liquid phase epitaxy of ZnO and characteristics of some Li-doped Mg/sub 0.06/Zn/sub 0.94/O/ZnO heterostructure
Thermogravimetry and differential thermal analysis (TG/DTA) were used to examine a process capable of fabricating homoepitaxial, single-crystalline MexZn1-xO (Me=Mg, Ga, etc.) films under thermodynamically stable conditions by liquid phase epitaxy. A liquid solution of alkaline metal (Li, Na, Cs) chlorides is employed at temperatures of 580–650°C. A reaction of Me+n-Cln/ZnCl2 with polycrystalline K2CO3 is applied to continuously form MexZn1-xO over a 16 h process cycle under ambient air atmosphere and pressure as shown by TG/DTA. Mirrorlike films with a thickness 3 µm have been grown. The high structural quality of the film with sharp interfacial transition from substrate to film has made it possible to observe a surface conductive channel. Temperature-dependent Hall measurement on Li-doped Mg0.06Zn0.94O/ZnO heterostructures under vacuum conditions discloses a high-resistivity state with 103 cm at 300 K and a low-resistivity state with <10 cm at 550 K.
Sato, H.; Ehrentraut, D.; Miyamoto, M.; Kim, K. J.; Schmidt, O. ; Kiesel, P. ; Fukuda, T. Thermal analysis of liquid phase epitaxy of ZnO and characteristics of some Li-doped Mg/sub 0.06/Zn/sub 0.94/O/ZnO heterostructure. Journal of the Electrochemical Society. 2007; 154 (3): H142-146.