We report a self-organized copper electrodeposition without imposed templates and induced additives. The deposit morphology on the silicon substrate varies from a branch to a parallel pattern by changing the applied voltage. We suggest that there are two essential factors for the formation of such kind of copper wire arrays. One is a proper electric potential distribution near the tip of the copper wire which dictates the direction of the solute transport. The other one is that the cathode overpotential and the equilibrium potential of reaction should remain unchanged at the growing interface.

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We demonstrate the fabrication of large scale nano- and micropatterned copper periodic structures on a silicon substrate without imposed templates. In the electrodeposition process, we employ a periodic variation voltage in an ultrathin layer of concentrated CuSO(4) electrolyte. The pattern can be controlled by varying the frequency of the applied potential. We suggest that the observed periodic micro-/nanostructures are caused by the lag of the migrating ion concentration profile versus the applied voltage profile near the tip of the growth.

A diamond-shaped P-doped ZnO nanostructure was fabricated on a Si (100) substrate by a chemical vapor deposition method. The photoluminescence properties of the ZnO nanostructure were studied with a temperature range from 81 to 306 K. At 81 K, a series of transitions of donor−acceptor pairs and their phonon replicas were observed in the PL spectrum. These results revealed that shallow-donor and deep-acceptor impurity bands existed in the P-doped ZnO nanostructure. From 81 to 111 K, the abnormal UV emission intensity was observed. The multiphonon scattering spectra were attributed to the interaction of electrons and phonons.

We report a copper electrodeposition with a microscopic structure of a regular ladder pattern on a silicon substrate where the ladder formation and evolution can be controlled by varying the electric field intensity during the electrodeposition. The deposit morphology varies from a periodic square-island structure to a ladder structure when the applied current is changed. The formation of a ladder structure with nanoparticles is related to the periodic potential measured across the electrodes. This method provides a deep insight into pattern formation in electrodeposition.

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Pearl-necklace-like Pb/PbSe heterostructure ordered arrays have been fabricated via a simple electrodeposition method. The phase structures, morphologies, and chemical compositions of the samples have been characterized by atomic force microscopy, field emission scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. Near-infrared absorption spectra of as-prepared Pb/PbSe heterostructure ordered arrays exhibit a blue shift. Raman spectra have been obtained using a confocal Raman spectrometer. The I-V curves show oscillations and nonlinear, symmetric characteristics under different potentials at 15 K.

Based on first-principles calculations, the coexistence of Ti vacancies (VTi) and O vacancies (VO) is first considered to study the origin of the ferromagnetic ordering in undoped rutile TiO2. The calculations show that VO can induce local magnetic moments in TiO2, however, the ferromagnetic (FM) exchange interaction of two VO is not strong enough to induce room-temperature (RT) ferromagnetism on their own in undoped TiO2. The FM coupling between two VTi is about four times stronger than that between two VO. More importantly, the FM coupling between two VTi is further enhanced after VO is introduced. Our results indicate that the electrons induced by VO mediate the long-range FM exchange interaction between two distant VTi. This maybe the ferromagnetism mechanism in undoped TiO2: VTi produce local moments while the electrons induced by VO mediated the long-range FM exchange interaction. The results are in excellent agreement with the experimental evidences that VO alone cannot induce RT ferromagnetism while VO can promote the ferromagnetic ordering in undoped TiO2.