Qiliang Wang

Ultraviolet photoelectrical properties of a n-ZnO nanorods/p-diamond heterojunction

The ultraviolet (UV) photoresponse properties of a n-ZnO nanorods/p-diamond heterojunction were investigated by studying the dark and photo I–V characteristics. It shows typical rectifying behavior with a rectification ratio of 3.2 and 8.8 at 5 V for the dark current and the photocurrent, respectively. The turn on voltage under UV illumination is three times lower than that under the dark current and the ideality factor of the device is decreased. The forward current under UV illumination is more than 4 times higher than the dark one at 10 V whereas the leakage current shows a little increase at −10 V. The electrical transport behaviors are investigated both under the dark current and the photocurrent. The photogenerated charges and their transfer processes were analyzed by surface photovoltage (SPV) measurements.

Fabrication, characterization and optical properties of TiO2 nanotube arrays on boron-doped diamond film through liquid phase deposition

TiO2 nanotube(TiNT) arrays were deposited on boron-doped diamond films by a liquid-phase deposition method with ZnO nanorod arrays as the template. The different morphologies of TiNTs have been obtained by controlling the morphology of ZnO template. The X-ray diffraction and energy-dispersive X-ray analysis show that the ZnO nanorod arrays template has been removed in the TiNTs formation process. The crystalline quality of the TiNTs is improved by increasing the annealing temperature. The band gap of the TiNTs is about 3.25 eV estimated by the UV-Vis absorption spectroscopy, which is close to the value of bulk TiO2. In the photoluminescence spectrum, a broad visible emission in a range of ca. 550–750 nm appears due to the surface oxygen vacancies and defects.

Plasmon resonance enhanced temperature-dependent photoluminescence of Si-V centers in diamond

Temperature dependent optical property of diamond has been considered as a very important factor for realizing high performance diamond-based optoelectronic devices. The photoluminescence feature of the zero phonon line of silicon-vacancy (Si-V) centers in Si-doped chemical vapor deposited single crystal diamond (SCD) with localized surface plasmon resonance (LSPR) induced by gold nanoparticles has been studied at temperatures ranging from liquid nitrogen temperature to 473 K, as compared with that of the SCD counterpart in absence of the LSPR. It is found that with LSPR the emission intensities of Si-V centers are significantly enhanced by factors of tens and the magnitudes of the redshift (width) of the emissions become smaller (narrower), in comparison with those of normal emissions without plasmon resonance. More interestingly, these strong Si-V emissions appear remarkably at temperatures up to 473 K, while the spectral feature was not reported in previous studies on the intrinsic Si-doped diamonds wh...

Fabrication of a hybrid structure of diamond nanopits infilled with a gold nanoparticle

A hybrid structure of a gold-nanoparticle (Au-NP)/diamond-nanopit has been fabricated by using a simple procedure of oxygen plasma etching of a Au-coated single crystal diamond. The nanopit is of an inversely truncated pyramidal shaped, and is filled with a Au NP located at the bottom. The formation process is thoroughly investigated. It was found that the structure was induced by the interaction of oxygen plasma etching and the plasma enhancement effect of Au NP. Here, the Au NPs enhanced the etching process, which is completely different from the masking effect in the formation of diamond nanowires/rods. In addition, after the Au NPs were removed by soaking in aqua regia, the structure served as a structural template for fabricating pyramid-structured poly(dimethylsiloxane) sheets.

Fabrication and Characteristics of TiO2 Nanotubes on Hemispherical Diamond Films Using ZnO Nanorods as Template

Zinc oxide (ZnO) nanorods (NRs) have been synthesized as a template to fabricate TiO2 nanotubes (TiNTs) on hemispherical diamond film by liquid-phase deposition (LPD) method. The process concerning the formation of TiNTs was analyzed. Based on the results of XRD and Raman spectroscopy, it is demonstrated that TiNTs was successfully obtained after removing ZnO NRs by chemical etching at room temperature. The TiNTs on hemispherical diamond film show higher performance photocatalysis, examined by the degradation of the reactive yellow 15 (RY15) solution. The corresponding mechanism is discussed.

Boron-Doped Diamond-Film-Based Two-Dimensional Electrode of Electrophoresis Tank*

Chemically robust conductive p-type boron-doped diamond (BDD) films are an important electrode material and have been widely applied in electrochemistry. In this study, BDD films are taken as a two-dimensional (2D) electrode in a electrophoresis tank system instead of the conventional one-dimensional platinum wire electrode. The theoretical simulations by finite element numerical analysis reveal that the 2D BDD electrodes have relatively high intensity and uniformity of electric field in the tank. Experimentally, the 2D BDD electrodes with smaller size show excellent properties for the separation of DNA fragments. The advantages of the 2D BDD electrodes with chemical inertness, sustainability, high intensity and uniformity electronic field, as well as reduced small size of electrophoresis tank would open a possibility for realizing new generation, high-performance biological devices.