Microstructural characteristics of tin oxide-based thin films on (0001) Al2O3 substrates: effects of substrate temperature and RF power during co-sputtering.

While tin oxides such as SnO and SnO2 are widely used in various applications, surprisingly, only a limited number of reports have been presented on the microstructural characteristics of tin oxide thin films grown under various growth conditions. In this paper, the effects of the substrate temperature and content of foreign Zn ion on the microstructural characteristics of tin oxide thin films grown by radio-frequency magnetron sputtering were investigated. The increase in substrate temperature induced change in the stoichiometry of the thin films from SnO(1+x) to SnO(2-x). Additionally, the phase contrast in the transmission electron microscopy image revealed that SnO(1+x) and SnO(2-x) phases were alternating in thin films and the width of each phase became narrower at high substrate temperature. The ternary zinc tin oxide thin films were deposited using the co-sputtering method. As the ZnO target power increased, the crystallinity of the thin films became poly-crystalline, and then showed improved crystallinity again with two types of phases.

Influence of synthesis temperature on the properties of Ga-doped ZnO nanorods grown by thermal evaporation.

This study examined the effect of the synthesis temperatures on the characteristics of vertically aligned Ga-doped ZnO (GZO) nanorods grown on a ZnO template by thermal evaporation using Zn and Ga sources. The increase in synthesis temperature at less than 700 degrees C induced stress relaxation relative to the ZnO template due to the suppression of defect generation by the formation of nanorods, while a further increase resulted in an increase in compressive strain due to dominant Ga doping. The increase in Ga concentration in the GZO nanorods with increasing synthesis temperature was also confirmed by X-ray photoelectron spectroscopy and photoluminescence. The best conductivity was observed in the GZO nanorods grown at 800 degrees C. On the other hand, the GZO nanorods synthesized at 900 degrees C showed less conductivity and weak near-band-edge emission properties due to the generation of defects from the excess Ga.

Synthesis and characterization of ZnO/MgZnO heterostructure nanorods by simple two-step evaporation.

ZnO-core/MgZnO-shell heterostructure nanorods with high aspect ratio were synthesized using a two-step thermal evaporation procedure, in which the core and the shell layers were formed separately at different temperatures. Microstructural characterization revealed a position dependence of the crystal structure and composition in the shell layer. The shell layer in the upper region consisted of MgO with quantum dot-like structure having cubic phases embedded in an amorphous oxide layer, while a Mg(0.35)Zn(0.65)O shell layer with a self-assembled superlattice structure of triple periodicity was formed in the middle region.