There has been a lot of attention on group III-nitride nanostructures for the nanoscale applications. Among those nanostructures, due to their outstanding electronic and optoelectronic properties such as high electron mobility, high saturation velocity because of their low effective mass, small band gap, terahertz/near-infrared emission, and high surface electron accumulation, indium nitride nanoparticles (InN NPs) have an increasing interest. There are a number of nanoparticle production methods to obtain the nanoscale InN crystal. However, all these methods include complex chemical procedures and the use of various precursor chemicals that are critical for the purity of the system. Pulsed laser ablation (PLA) method is a promising method for nanoparticle production. A number of novel semiconductor, nitride, and metal and metal oxide nanoparticles can be successfully produced by the PLA method. Compared to other methods, PLA, offers a versatile way of producing colloidal, highly pure, and agent-free nanocrystals.
Generation of InN Nanocrystals in Organic Solution Through Laser Ablation of High Pressure Chemical Vapor Deposition Grown InN Thin Film
S. Alkis, M. Alevli, S. Burzhuev, H. A. Vural, Ali K. Okyay and B. Ortaç Journal of Nanoparticle Research, vol. 14, pp. 1048 (2012)
Blue luminescent colloidal silicon nanocrystals (Si-NCs) were produced in a two-stage process. In the first step, synthesis of Si-NCs was achieved by femtosecond pulsed laser ablation of a silicon wafer, which was immersed in deionized water. The size and the structural and the chemical characteristics of colloidal Si-NCs were investigated by TEM and EDAX analyses, and it is found out that the Si-NCs are in spherical shape and the particle diameters are in the range of 5−100 nm. In the second step, ultrasonic waves and filtering chemical-free post-treatment of colloidal Si-NCs solution was performed to reduce the particle size. High-resolution TEM (HRTEM) studies on post-treated colloidal solution clearly show that small (1−5.5 nm in diameter) Si-NCs were successfully produced. Raman spectroscopy results clearly confirms the generation of Si nanoparticles in the crystalline nature, and the Raman scattering study of post-treated Si-NCs confirms the reduction of the particle size. The UV−vis absorption and photoluminescence (PL) spectroscopy studies elucidate the quantum confinement effect of Si-NCs on the optical properties. The colloidal Si-NCs and post-treated Si-NCs solutions present strong absorption edge shifts toward UV region. Broadband PL emission behavior is observed for the initial colloidal Si-NCs, and the PL spectrum of post-treated Si-NCs presents a blue-shifted broadband PL emission behavior due to the particle size reduction effect.
Post-Treatment of Silicon Nanocrystals Produced by Ultra-Short Pulsed Laser Ablation in Liquid: Towards Blue Luminescent Nanocrystal Generation
S. Alkis, Ali K. Okyay and B. Ortaç Journal of Physical Chemistry C, vol. 116, pp. 3432-3436 (2012)
Two-dimensional MoS2 nanosheets (2D MoS2 NS) and fullerene-like MoS2 nanostructures (3D MoS2 NS) with varying sizes are synthesized by nanosecond laser ablation of hexagonal crystalline 2H-MoS2 powder in organic solution (methanol). Structural, chemical, and optical properties of MoS2 NS are characterized by optical microscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Raman and UV−vis−near infrared absorption spectroscopy techniques. Results of the structural analysis show that the obtained MoS2 NS mainly present a layered morphology from micrometer to nanometer sized surface area. Detailed analysis of the product also proves the existence of inorganic polyhedral fullerene-like 3D MoS2 NS generated by pulsed laser ablation in methanol. The possible factors which may lead to formation of both 2D and 3D MoS2 NS in methanol are examined by ab initio calculations and shown to correlate with vacancy formation. The hexagonal crystalline structure of MoS2 NS was determined by XRD analysis. In Raman spectroscopy, the peaks at 380.33 and 405.79 cm−1 corresponding to the E1 2g and A1g phonon modes of MoS2 were clearly observed. The colloidal MoS2 NS solution presents broadband absorption edge tailoring from the UV region to the NIR region. Investigations of MoS2 NS show that the one-step physical process of pulsed laser ablation−bulk MoS2 powder interaction in organic solution opens doors to the formation of “two scaled” micrometer- and nanometer-sized layered and fullerene-like morphology MoS2 structures.
Synthesis of colloidal 2D/3D MoS2 nanostructures by pulsed laser ablation in an organic liquid environment
T. Oztas, H. S. Sen, E. Durgun and B. Ortaç Journal of Physical Chemistry C, vol. 118, pp. 30120–30126 (2014)
Scientific research involving nanotechnology has grown exponentially and has led to the development of engineered nanoparticles (NPs). Silica NPs have been used in numerous scientific and technological applications over the past decade, necessitating the development of efficient methods for their synthesis. Recent studies have explored the potential of laser ablation as a convenient way to prepare metal and oxide NPs. Due to its high silica content, low cost, and widespread availability, sugarbeet bagasse is highly suitable as a raw material for producing silica NPs via laser ablation. In this study, two different NP production methods were investigated: laser ablation and NaOH treatment. We developed a novel, one-step method to produce silica NPs from sugarbeet bagasse using laser ablation, and we characterized the silica NPs using environmental scanning electron microscopy (ESEM), energy dispersive spectrometry (EDS), dynamic light scattering (DLS), transmission electron microscopy (TEM), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR–FTIR), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. EDS analysis and XPS confirmed the presence of silica NPs. The NPs produced by laser ablation were smaller (38–190 nm) than those produced by NaOH treatment (531–825 nm). Finally, we demonstrated positive effects of silica NPs produced from laser ablation on the growth of microalgae, and thus, our novel method may be beneficial as an environmentally friendly procedure to produce NPs.
Novel one step synthesis of silica nanoparticles from sugarbeet bagasse by laser ablation and effect on growth of fresh water algea culture
N. O. San, C. Kurşungöz, Y. Tümtaş, Ö. Yaşa, B. Ortaç and T. Tekinay Particuology, vol. 17, pp. 29-35 (2014)