M. Highasiata

Bio: M. Highasiata is an academic researcher from Kyushu University. The author has contributed to research in topics: Pulsed laser deposition & X-ray photoelectron spectroscopy. The author has an hindex of 1, co-authored 3 publications receiving 10 citations.

Influence of Sb as a Catalyst in Synthesize of Sb Doped ZnO Nanostructures Using Nanoparticle Assisted Pulsed Laser Deposition for UV LED Applications

Abstract: The paper deals with synthesis of Sb and Sb–Al co-doped ZnO nanowires using nanoparticle assisted pulsed laser deposition (NAPLD) by considering Sb as a catalyst. The mechanism of the growth initiation of nanostructures from the Sb droplets is analyzed at varying growth temperature. Nanowires and nanosheets of different orientation were synthesized. With ZnO:Al target and Sb coated Si as substrates, at a growth temperature of 750 °C, random oriented high density nanowires with a diameter of about 1 μm and a length up to a few tens of micrometer were synthesized. The suppression of A1T modes and E1(L0) modes from Raman spectroscopy confirming that depletion of oxygen vacancies. XPS analysis confirming that the Sb would substitute for Zn(Sbzn) instead of oxygen Al–O bonds, leading to excess of oxygen, neutralizing the oxygen vacancies. The Sb–Al co-doped nanowires annealed at 650 °C showed a strong UV emission and reduction in visible emission as compared to the Sb–Al co-doped nanowires annealed at 450 °C. This confirms that the Sb–Al co-doped posses high stoichiometric nature, good structural and optical properties. To investigate the p-type conductivity of the Sb–Al co-doped nanowires, a homo p–n junction was prepared by synthesizing Sb–Al co-doped ZnO nanowires on the pure ZnO surface. The I–V characteristics of the homo P–N junction were investigated and a rectifying behavior was observed confirming the formation of p-type. Hence the Sb mono-doped and co-doped ZnO nanowires synthesized by using Sb as catalyst posses good structural and optical properties with good crystallization quality and high stoichiometry nature, hence it is highly suitable for light emitting device applications.

Influence of Sb Coated Substrates in Development of Vertical and Random Oriented ZnO Nanostructures for UV LED Application Using Nano Particle Assisted Pulsed Laser Deposition

Abstract: This research highly focuses towards influence of different paprmaters in development of Sb doped ZnO nanostructures using Nano Particle Assisted Pulsed Laser Deposition by using Sb coated substrate.different types of nanostructures were synthesized with vartion in growth temperature. Nano wires generated from Sb coated silicon substrate posses a sharp UV emission from room temperature PL. vertically aligned ZnO nanowires were grown on different ZnO buffer layer thickness ranging from 100 to 1600 nm. With increase in buffer layer thickness a strong UV emission with improved structural properties are observed, which are highly suitable for optoelectronic device application.

Histidine-Capped ZnO Nanoparticles: An Efficient Synthesis, Spectral Characterization and Effective Antibacterial Activity

Abstract: In this article, an efficient synthesis of histidine-capped ZnO nanoparticles was carried out in absolute ethanol by using solvothermal technique. The synthesized nanoparticles were further characterized by using different techniques such as powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), Fourier transfer infrared (FTIR), UV-visible spectroscopy, thermal analysis (TG/DTG/DTA) and photoluminescence spectroscopy. The XRD measurement reveals that the prepared nanoparticles have hexagonal wurtzite structure. From XRD data, the average crystalline size is calculated to be 22 nm according to half width of (1 0 1) diffraction peak using Debye-Scherrer formula. Moreover, the antibacterial activities of nanoparticles sample have been performed under standard method. The antibacterial activities of histidine-capped zinc oxide nanoparticles are tested against human bacterial pathogen such as Staphylococcus aureus, Escherichia coli, Klebsiella sp., Enterococcus faecalis and Pseudomonas aeruginosa by using agar well diffusion method. Besides, antibacterial activities of ZnO nanoparticles (20 to 60 μg) are compared with four well-known antibiotics viz., Amikacin (30 mcg), Ciprofloxacin (5 mcg), Gentamicin (5 mcg) and Norfloxacin (10 mcg). From antibacterial studies, it has been concluded that if the concentration of histidine-capped ZnO nanoparticles increases, then the antibacterial activities also increase.

Electrical and optical properties of Sb-doped ZnO thin films synthesized by sol–gel method

Abstract: Sb-doped ZnO thin films with different values of Sb content (from 0 to 11 at%) are deposited by the sol–gel dip-coating method under different sol concentrations The effects of Sb-doping content, sol concentration, and annealing ambient on the structural, optical, and electrical properties of ZnO films are investigated The results of the X-ray diffraction and ultraviolet-visible spectroscopy (UV-VIS) spectrophotometer indicate that each of all the films retains the wurtzite ZnO structure and possesses a preferred orientation along the c axis, with high transmittance (> 90%) in the visible range The Hall effect measurements show that the vacuum annealed thin films synthesized in the sol concentration of 075 mol/L each have an adjustable n-type electrical conductivity by varying Sb-doping density, and the photoluminescence (PL) spectra revealed that the defect emission (around 450 nm) is predominant However, the thin films prepared by the sol with a concentration of 025 mol/L, despite their poor conductivity, have priority in ultraviolet emission, and the PL peak position shows first a blue-shift and then a red-shift with the increase of the Sb doping content