By the formation of ZnO and Pt nanocomposites, it is found that the bandgap emission can be greatly enhanced, while the defect emission is suppressed to the noise level. The photoluminescence intensity ratio between the bandgap and defect emission can be improved by up to 10 3 times. The underlying mechanism behind enhancement of the bandgap emission and quenching of the defect emission is a combination of the energy transfer between defects and surface plasmon resonance in Pt nanoparticles, as well as electron-hole pair generation and recombination in the ZnO nanorods. Our results will be very useful to manufacturers of highly efficient optoelectronic devices.

ZnO/SnO nanocomposites have been designed to enhance the band edge emission and suppress the defect emission of ZnO nanorods simultaneously. It is found that the intensity ratio between the band edge and defect emission can be improved by up to 4 orders of magnitude. The underlying mechanism is interpreted in terms of surface modification as well as carrier transfer from SnO nanoparticles to ZnO nanorods. Our approach is very useful for creating highly efficient optoelectronic devices.

A novel phenomenon called the photoelastic effect had been observed in ZnO nanorods, along with a number of intriguing anomalies. With increasing excitation power, it was found that the A 1 (LO) phonon exhibited a red-shift in frequency, on top of a blue-shift in the photoluminescence (PL) peak energy. In addition, the temperature-dependent photoluminescence spectra behaved quite differently under high and low excitation power. All our results can be accounted for by the photoelastic effect, in which the built-in surface electric field was screened by photoexcited electrons and holes. Through the converse piezoelectric effect, the internal strain was therefore altered. Our results make possible a new thrust for manipulating the physical properties of ZnO nanorods, and should prove very useful in the application of optoelectric devices.

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Optical integration is essential for practical application, but it remains unexplored for nanoscale devices. A newly designed nanocomposite based on ZnO semiconductor nanowires and Tb(OH)3/SiO2 core/shell nanospheres has been synthesized and studied. The unique sea urchin-type morphology, bright and sharply visible emission bands of lanthanide, and large aspect ratio of ZnO crystalline nanotips make this novel composite an excellent signal receiver, waveguide, and emitter. The multifunctional composite of ZnO nanotips and Tb(OH)3/SiO2 nanoparticles therefore can serve as an integrated nanophotonics hub. Moreover, the composite of ZnO nanotips deposited on a Tb(OH)3/SiO2 photonic crystal can act as a directional light fountain, in which the confined radiation from Tb ions inside the photonic crystal can be well guided and escape through the ZnO nanotips. Therefore, the output emission arising from Tb ions is truly directional, and its intensity can be greatly enhanced. With highly enhanced lasing emissions in ZnO-Tb(OH)3/SiO2 as well as SnO2-Tb(OH)3/SiO2 nanocomposites, we demonstrate that our approach is extremely beneficial for the creation of low threshold and high-power nanolaser.