Papers by Keyword: N-Doping

Abstract: Co-doping of nanosilver, carbon and nitrogen is done on titania to get improved photodegradation of pollutants when compared to single doping. Anion doping extends the absorption of TiO2 to the visible region; whereas noble metal NP doping prevents the recombination of photoinduced electrons and holes. Doped TiO2 prepared using sol gel method allows efficient dispersion of nano silver and thus enhances the photodegradability. X-ray Diffraction analysis shows the efficient dispersion of incorporated nano silver over anatase TiO2. The visible light absorption is confirmed from UV-Vis Diffuse Reflectance spectral studies. Photocatalytic activity is investigated by the degradation of methyl orange as a model pollutant. Efficient degradation in visible light shows the synergetic effect of carbon and nitrogen doping as well as nano silver loading on the performance of TiO2.

Abstract: N doped ZnO thin films were prepared by magnetron sputtering. The effect of bias voltage, N₂ flow and introducing of Al on the behavior of N doping into ZnO films were investigated. The results show that there is little help for N doping into the ZnO films by just adjusting N flow rate because the magnetron sputtering method has a relative weak ability on dissociating the N₂. The data of co-doping of Al and N into ZnO films revealed that co-doping is an effective way to advance the N doping into ZnO films. The coordination of Al doping and bias voltage could help the N doping effectively.

Abstract: CNTs were treated with hydrazine hydrate and diethylenetriamine, respectively. Scanning electron spectroscopy (SEM) observation showed that the doped CNTs kept the length/diameter ratio of pristine CNTs. X-ray photoelectron spectroscopy (XPS) characterized that nitrogen can be doped to CNTs. XPS analysis further indicated that C/N atomic ratio of CNTs treated by hydrazine hydrate is 95/2, four times of CNTs treated by diethylenetriamine, which is 96/0.5. The hydrophilicity for N-doped CNTs (N-CNTs) is much improved and enhanced by increasing N proportion. As electrode material of supercapacitor, nitrogen functional groups contribute pseudo-Faradic capacitance, but its cyclic performance still need to be improved. Thanks to the good hydrophilicity for N-CNTs that improves the wettability of CNTs for electrolyte; the specific capacitance of N-CNTs is still slightly higher than pristine CNTs after cycling.

Abstract: Crystalline ZnO films were grown on Y-stabilized ZrO2 substrates heated at 300 - 600 °C in NH3 atmosphere. It is clarified from Fourier transform infrared measurements that N-doped ZnO films grown at 350 and 400 °C contain N-C and Zn-H bonds. In the devices of n-type ZnO/N-doped ZnO/Au, a good rectification characteristic is attained for an N-doped ZnO film deposited at 300°C, whereas a linear current vs. voltage characteristic is seen for a film deposited at 500 °C.

Abstract: Graphitic N-free and N-doped carbon molecular sieves were prepared using zeolite NaY as a template via one-step chemical vapor deposition method (CVD) with propylene and acetonitrile as N-free and N-doped carbon precursors, respectively. The morphology, structure and properties of the carbons prepared were characterized via XRD, SEM, TEM and adsorption measurements. A large proportion of pore volume is associated with micropores in the carbons prepared. A high hydrogen uptake capacity is observed.

Abstract: We present a structural and optical investigation of nitrogen-doped single crystals of cubic silicon carbide prepared by the continuous feed - physical vapour transport method. Self-nucleated crystals were produced which exhibited well faceted square and triangular shapes. KOH etching was used to characterize the structural defects, like stacking faults and dislocations. The effect of changing the nitrogen flow rate on the different crystalline orientations was investigated by Raman spectroscopy and low temperature photoluminescence techniques.

Abstract: We have investigated the influence of several growth parameters on the incorporation of doping species in the case of 3C-SiC layers grown by CVD on silicon. This includes nitrogen (both intentional and residual) as well as residual aluminum. All concentrations have been determined by SIMS (Secondary Ion Mass Spectrometry). First, we investigated the effect of the growth temperature, growth rate and C/Si ratio on the doping level of (100) oriented layers. Then, we compared the change in nitrogen incorporation versus nitrogen flow rate for layers grown on (100), (111), (110) and (211) oriented wafers.