Papers by Keyword: Dopant

Abstract: (1-x)BiFeO₃-xBaTiO₃-0.01KVO₃ with (x = 0.33 and 0.38) (abbreviated FTV33 and FTV38) was successfully prepared using three precursors that had been synthesized before the calcination process. BaTiO₃ was synthesized using the coprecipitation method, BiFeO₃ was synthesized using the sol-gel auto-combustion method, and KVO₃ was synthesized using the conventional solid-state method. Thermal analysis was carried out to determine the calcination temperature from 600 0C for 2h to 600 0C for 4h. X-ray diffraction (XRD) has been carried out to identify the phase after calcination at temperatures, respectively. The phase identification of the XRD pattern has been carried out by Match software shows that the powder and FTV33 and FTV38 have a pseudo-cubic structure with a P4mm space group and rhombohedral with an R3c space group. The XRD pattern is refined by the Rietveld method by Rietica software and the crystalline size is determined by MAUD software. The doping effect of KVO₃ on its electrical properties was systematically investigated and show that FTV33 is more conductive and has larger capacitance grains. Based on the previous XRD analysis, Ba²⁺ and K⁺ ions replaced Bi³⁺ at site A. On the other hand, Ti⁴⁺ and V⁵⁺ substituted Fe³⁺ at site B which was different from the host's oxidation state.

Abstract: The presence of N-dopant in Reduced Graphene Oxide has contributed to the change of their optical band gap. In this research, this mechanism has been implemented to synthesize nitrogen-doped graphenic carbon (NGC) proposed as an n-type semiconducting layer. The graphenic-based carbon (GC) was derived from coconut shells by a green synthesis method. The two sources of nitrogen dopants were prepared from ammonia water (NH₄OH) and urea (CH₄N₂O). Synthesis of NGC was conducted from GC and a particular dopant with a ratio of 1:20 and 1:40 by wet mixing. Then the NGC solution was deposited onto a 1x1 cm² glass substrate using a nanospray method to form a layer. X-ray diffraction (XRD) of NGC film has indicated an amorphous characteristic of the film. According to Energy Dispersive X-ray (EDX) spectroscopy, the presence of nitrogen as a doping material in the GC was successfully demonstrated. The SEM cross-section image has performed the NGC layer on the substrate. Absorbance analysis from UV-Vis spectroscopy also explains the occurrence of electronic transitions, both in the form of a solution and a layer of NGC material. The further analysis explained that the optical band gap of the NGC material ranged from 1.66 – 1.86 eV, which exhibits the semiconductor characteristic of the NGC material.

Abstract: In the present work we pay an attention to the molecular structural changes between raw coal and its enriched, dense productions. Bituminous Ukhaa-Khudag coal in the form of an enriched, dense coal product is currently used as an energy source by Mongolian consumers for everyday need. There are three types of samples from one source: it is a raw coal (sample 1) and two of industrial prod- ucts as an enriched, dopant (organic based) added coal (sample 2) and simply enriched coal (sample 3). The raw coal general characterization is given through the elemental analysis, thermogravimetry analysis, moreover functional groups were identified by Fourier Transform infrared spectroscopy. The differences in the FTIR spectra of the samples were done.Some details are as follows: hydroxyl group vibrations are existing, rather weak in agreement of TG result; vibrations of aliphatic group were rarely in the long wave near region, carbonate minerals in the region of 1300-900 cm−1 are visible but overlapped, and an isolated out-of-plane deformational vibration (around 800 cm−1) or two-adjacent (800-750 cm−1) or three-adjacent (around 700 cm−1) of sp2-hybrid bonded aromatic CHx-groups were still presenting.After the processing hydroxyl group bands were affected in enriched coals, sample 2 and 3. In the spectrum of the sample 2 the long wave bands were intensively blurred.Industry processing retains an amount of water in the productions. Water excess influenced absorbance bands were able to be removed via the drying processing, however, the affection to the spectral struc- ture in sample 2 was unrecoverable.

Abstract: This contribution, based on literature review, presents a general overview of properties and applications of transparent conductive oxides, TCO. The requested properties of TCO are a high conductivity associated to high transparency in a wide wavelength range. The relation between the techniques used for deposition or growing TCO and the possibility of their doping with appropriate dopant and concentration were discussed relatively to their applications and properties. Thus, we present in this part, the various possible techniques for growing TCO and discuss the effect of the temperature on the functional properties. This self-consistent presentation is also considered to introduce a better understanding of the expected requirements for TCO integrated as transparent electrodes in photovoltaic cells and modules. These developments of TCO for photovoltaic applications will be presented in a second publication.

Abstract: The intrinsic hardness, high abrasive wear resistance, and corrosion properties of hard chrome coatings have resulted in their wide industrial application. However, chrome plating involves hazards associated with chrome 6+ which affect human health and drive the need to identify viable alternatives. This study investigated the addition of Cirrus alumina Dopant™ to a low phosphorus electroless nickel bath to evaluate the performance of the resulting nanocomposite coating as a potential replacement for hard chrome. A comprehensive comparison for the performance of coatings for alumina doped electroless nickel and a pure low electroless nickel coating were investigated. Results showed that Cirrus doped electroless nickel possessed a minimum hardness of 850HV_0.1, high corrosion resistance, excellent abrasive wear resistance, and a Taber Wear Index of 2.25mg/1000 cycles. These attributes suggest Cirrus Dopant™ for electroless nickel may offer an outstanding candidate to replace hard chrome coatings in many applications.

Abstract: We report significant advancements in corona-based non-contact capacitance-voltage (CnCV) metrology recently developed for comprehensive C-V characterization of SiC and other wide bandgap semiconductors. The technique answers the industries needs for nondestructive, cost-effective C-V dopant monitoring for material and device development and manufacturing control. Excellent precision and matching to mercury probe CV is demonstrated for SiC, Ga₂O₃, GaN and AlGaN/GaN structures over a concentration range from 10¹⁴cm^-3 to 2x10¹⁹cm^-3. The emphasis in the present work is on improvement of CnCV in dopant depth profiling resolution and measurement throughout. This is achieved with a variable charge method that in-situ adjusts corona charging increments in response to changes in dopant concentration. Results are presented for multi-layer epitaxial SiC and for 2DEG in AlGaN/GaN HEMT structures. The latter represents an extreme case of high-low concentration profiling with a transition from 10²⁰electrons/cm^-3 in the 2D electron gas to a fully depleted well and dopant concentration in the 10¹⁵cm^-3 range.

Abstract: This paper reported the investigation on gallium, Ga addition into In-4.8Zn lead-free solder to improve its wettability performances. The effect of addition of Ga in In-4.8Zn solder alloy was studied. The results show with the addition of 0.5% Ga into the In-4.8Zn composition, the spreading area of In-4.8Zn-0.5Ga solder on copper increase between 35.71 and 43.75 %. Hence, as the spreading area increases, the contact angle decreased from between 22.09 to 39.71 %. Additionally, the addition of Ga as dopant increased the thickness of IMCs layer.

Abstract: The OLEDs were fabricated with the structure of ITO/m-MTDATA(20nm)/NPB(10nm)/ DPVBi:BCzVBi(15 nm,x%)/TPBi(10 nm)/Alq3(20nm)/Cs₂CO₃：Ag₂O(2nm,20%)/ Al (100 nm) by using the method of fluorescent dyes dopant. The effect of different DPVBi:BCzVBi doping concentration(x=5,8, 10 and 15) on the properties of blue light device was studied．Results show that when the mass fraction of fluorescent dye BCzVBi was 10%, performances of the device were the best. This device had a maximum current efficiency of 4.19 cd /A and maximum luminance of 14757 cd /m² at 17 V.When the driving voltage changed from 8 to 17 V, the efficiency of the devices had been rising. There are not the phenomenon of efficient roll-off.

Abstract: Oil is one of the most important energy sources for the world and will likely remain so for many decades, even in the most optimistic projection about the growth of alternative energy sources. Petroleum industry nowadays faced a problem when the naphthenic acid (NA) compound naturally present in the acidic crude oil tends to induce corrosion in oil refining process. Total Acid Number (TAN) represent the amount of naphthenic acid in the oil with the permissible limit of TAN in crude oil is less than 1. Various methods had been used to remove NA in crude oil such as dilution and caustic washing. But all methods have their own weakness. Hence, in order to overcome the acidic crude oil problem, a new catalytic deacidification technique will be introduced in this study. Three types of crude: Petronas Penapisan Melaka Heavy Crude (Crude A) and Light Crude (Crude B) and Korean Crude (Crude C) were studied. Parameters studied were dosing amount of basic chemical used, catalyst calcination temperature, and percentage of the basic chemical in the co-solvent. The basic chemical used in this study was ammonia solution in ethylene glycol (NH₃-EG). By using Ca/Al₂O₃ catalyst with calcination temperature of 10000C, the results showed 66.7% (1000 mg/L of NH₃-EG) reduction in TAN for crude A, 53.9% reduction for crude B while for crude C the percentage of TAN reduction was 41% only. Addition of Cu as a dopant in this study had increased the TAN reduction for all three types of crude oil. TAN in crude A (80% of TAN reduction) and crude B (77% of TAN reduction) were successfully reduced to less than 1 with only using 1000 mg/L of NH₃-EG with the aids of Cu/Ca (10:90)/Al₂O₃ catalyst at calcination temperature of 10000C while for crude C the TAN was still higher than 1 but the percentage of TAN reduction increased to 46%.

Abstract: YAl₃(BO₃)₄ doped with three rare earth (RE) ions namely Ce^{3 +}, Dy³⁺ and Tb³⁺ were prepared by the conventional solid state diffusion method. The phosphors were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) techniques. PL spectra of Ce-doped samples showed the Ce³⁺ emission characteristic due to the 5d-4f transition. Dy-doped sample upon excitation at 351 nm, showed peaks corresponding to the ⁴F_9/2→⁶H_15/2 and ⁴F_9/2→⁶H_13/2 transitions. PL spectra of Tb-doped sample showed peaks corresponding to the ⁵D₃→⁷F_J transition. Upon excitation at 364 nm, the enhanced luminescence observed in Ce³⁺ co-doped YAl₃(BO₃)₄:Tb³⁺/Dy³⁺ phosphors is understood as due to energy transfer from Ce³⁺ to Tb³⁺/Dy³. The color purity has also been verified by using the chromaticity diagram.