ZnO@Si(100) and ZnO@Si(111): Hydrothermal Synthesis, Morphology, and Lasing Characteristics

Abstract

Microstructures have been formed on single-crystal silicon substrates of different crystallographic orientations, (111) and (100), under “soft” hydrothermal conditions. Well-faceted ZnO microcrystallites were obtained on the Si(111) surface, whereas the Si(100) substrate surface was covered with willemite (Zn₂SiO₄) crystallites, and zinc oxide microcrystallites were observed in only a narrow region ∼1 mm wide over the substrate edge. These results indicate clear influence of the crystallographic orientation of silicon substrates on the processes of crystal formation and microstructure growth under conditions of low-temperature hydrothermal synthesis. Low-threshold effective lasing has been detected on well-faceted zinc oxide crystallites under optical excitation.