We demonstrate the fabrication of solution based low temperature-processed p-type ZnO NRs doped with phosphorous by using a spin-on-dopant method coupled with a hydrothermal process. We confirmed the incorporation of phosphorous dopants into a ZnO crystal by analyzing SIMS profiles, together with the evolution of the photoluminescence spectra. It is further revealed that the electrical properties of the p-type ZnO/n-type Si heterojunction diode exhibited good rectifying behavior, confirming that p-type ZnO NRs were successfully formed. In addition, we demonstrate that a piezoelectric nanogenerator with p-type ZnO NRs made on a glass substrate shows large enough power to drive polymer dispersed liquid crystal displays.

Visible light-emitting Ce-doped ZnO nanorods [NRs] without a post thermal annealing process were grown by hydrothermal method on a Si (100) substrate at a low temperature of 90°C. The structural investigations of Ce-doped ZnO NRs showed that the Ce3+ ions were successfully incorporated into the ZnO lattice sites without forming unwanted Ce-related compounds or precipitates. The optical investigation by photoluminescence spectra shows that the doped Ce3+ ions in the ZnO NRs act as an efficient luminescence center at 540 nm which corresponds to the optical transition of 5d → 4f orbitals in the Ce3+ ions. The photoluminescence intensity of the Ce-doped ZnO NRs increased with the increasing content of the Ce-doping agent because the energy transfer of the excited electrons in ZnO to the Ce3+ ions would be enhanced by increased Ce3+ ions.

We report a controllable way of changing the emission patterns of GaN-based blue light-emitting diodes (LEDs) using ZnO nanorods (NRs) grown hydrothermally. The shape of the ZnO NRs was controlled using seed layers for flower, askance, and vertical structures. The electrical properties of the LEDs with the ZnO NRs did not degrade, while the integrated electroluminescence intensity increased compared with that of the bare LEDs. The emission patterns of the LEDs were broadened as the inclination angle of the ZnO NRs increased. These are attributed to the ZnO NRs acting a role in scattering and guiding the light wave efficiently.

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In this study, we fabricated and characterized three dimensional (3D) silicon (Si)/zinc oxide (ZnO) hybrid subwavelength structures to investigate their antireflective properties. Si nanorods (SiNRs) were fabricated by electrochemical etching, and subsequentially we grew ZnO NRs on SiNR as templates by using hydrothermal synthesis. The morphological and optical properties of hybrid Si/ZnO subwavelength structures were investigated by scanning electron microscopy (SEM) and ultra violet-visible-near infrared (UV-VIS-NIR) spectrophotometer, respectively. The reflectance on SiNRs is greatly reduced comparing with that on the conventional textured Si surface. Moreover, the hybrid SiNR/ZnO NR structures gave the lowest reflectance (< 3%) throughout the broadband spectrum range. We suggest that the combination of SiNRs and ZnO NRs trap light, leading to suppressing light reflection and increasing light scattering to the hybrid structures.

Surface plasmon (SP)-enhanced light emission mechanism has been investigated for the Ag-coated ZnO/Al2O3 core/shell nanorods (NRs). Structural characterizations showed that the ZnO NRs were covered by conformal Al2O3 layer and coated by Ag nanoparticles (NPs). The optical studies by photoluminescence (PL) showed abnormal variation of PL intensity with increasing the thickness of Al2O3. For the Ag NPs-coated ZnO NRs without Al2O3 shell layer, the PL emission quenched due to direct transfer of the photo-excited electrical carriers from ZnO NRs to Ag NPs. With thin Al2O3 layers less than 15 nm, the PL intensity increased with increasing the thickness of Al2O3 layers due to weakening of the Förster-type energy transfer while strong SP-mediated PL emission enhancement. For thicker Al2O3 layers than 15 nm, however, the PL intensity decreased with increasing the thickness of Al2O3 layers due to weakening of SP-mediated PL emission enhancement.

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