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Potential well
About: Potential well is a research topic. Over the lifetime, 1430 publications have been published within this topic receiving 30812 citations.
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TL;DR: In this article, high-resolution electron energy loss spectroscopy (HR-EELS) was used to examine annealed and hydrogenated nanodiamond films with 3-5-nm grains.
8 citations
TL;DR: The results suggest that the present silicon NCs with pH-sensitive tunable light emission could find promising potential applications as optical sources, bio-sensors, etc.
Abstract: We fabricated a silicon nanocrystal (NC) suspension with visible, continuous, tunable light emission with pH sensitivity from violet to blue-green. Transmission electron microscopy (TEM) images and X-ray diffraction (XRD) pattern analysis exhibit the highly crystalline nanoparticles of silicon. Photoluminescence (PL) spectra and photoluminescence excitation (PLE) spectra at different pH values, such as 1, 3, 5, 7, 9, and 11, reveal the origins of light emission from the silicon NC suspension, which includes both the quantum confinement effect and surface bonding. The quantum confinement effect dominates the PL origins of silicon NCs, especially determining the tunability and the emission range of PL, while the surface bonding regulates the maximum peak center, full width at half maximum (FWHM), and offsets of PL peaks in response to the changing pH value. The peak fitting of PLE curves reveals one of the divided PLE peaks shifts towards a shorter wavelength when the pH value increases, which implies correspondence with the surface bonding between silicon NCs and hydrogen atoms or hydroxyl groups. The consequent detailed analysis of the PL spectra indicates that the surface bonding results in the transforming of the PL curves towards longer wavelengths with the increasing pH values, which is defined as the pH sensitivity of PL. These results suggest that the present silicon NCs with pH-sensitive tunable light emission could find promising potential applications as optical sources, bio-sensors, etc.
8 citations
TL;DR: In this paper, the average size of the microcrystallites, depending on post-annealing temperature and time, is on the order of magnitude of nanometer, and large blue shifts of absorption edge were observed in a wide range from 300 to 1500 nm.
Abstract: Semiconductor InSb microcrystallites were embedded in SiO2 thin films by rf cosputtering technique. Structures of the thin films were characterized by transmission electron microscopy, x-ray diffraction, and x-ray photoelectron spectroscopy. Average size of the microcrystallites, depending on post-annealing temperature and time, is on the order of magnitude of nanometer. Absorption spectra of the films were measured and large blue shifts of absorption edge were observed in a wide range from 300 to 1500 nm. The blue shifts were attributed to the quantum confinement effect and explained in the model of effective-mass approximation.
8 citations
TL;DR: In this article, Ba2+ and Zn2+ ions are incorporated in the Cadmium sulfide (CdS) crystal structure without changing the original structure and the particle size was increased slightly as a function of Ba 2+ concentration and the reason for this change was ascertained to the change in ionic radius of the Ba 2 wt.
Abstract: Cadmium sulfide (CdS) is a suitable candidate in the II–VI wide band gap semiconductor family with robust applications in imaging, optical and optoelectronic fields. In the present investigations, various studies have shown that Ba2+ and Zn2+ ions are well incorporated in the CdS crystal structure without changing the original structure. The particle size was increased slightly as a function of Ba2+ concentration and the reason for this change was ascertained to the change in ionic radius of the Ba2+ and Cd2+ ions. UV–vis spectral studies showed that the absorption intensity was increased more due to the addition of Ba2+ ions and thereby the optical band gap has undergone a red-shift. This band gap narrowing occurrence was ascertained to the quantum confinement effect. The photoluminescence (PL) emission peaks were observed at 384 nm (UV region), 483 nm (blue), 523 nm (green), and 685 nm (red). The Ba2+ ion (2 wt. %) incorporation into Zn:CdS crystal structure showed an excellent optical property and offered various color emissions with high intensity. The primary studies (XRD, SEM) confirmed the crystalline nature and surface morphological information of the samples. The elemental and compositional analysis were made using EDX and FTIR results and they verified the purity of the synthesized nanomaterials. As the composition of Ba2+ and Zn2+ ion-incorporated CdS can be successfully prepared using facile co-precipitation method without using a capping agent, which possesses good absorption in UV region and offers an opportunity to tune the PL emission, these materials can be selected for the solar cells and white LED applications.
8 citations
TL;DR: In this article, a simple solvothermal method using a domestic microwave oven X-ray powder diffraction measurement indicates the amorphous nature of the as-prepared sample and calcined samples were obtained by annealing the sample at different temperatures, viz 400, 500, 600 and 700 o C.
Abstract: Fe2O3 nanoparticles have been prepared by a simple solvothermal method using a domestic microwave oven X-ray powder diffraction measurement indicates the amorphous nature of the as-prepared sample Calcined samples were obtained by annealing the as-prepared sample at different temperatures, viz 400, 500, 600 and 700 o C Transmission electron microscopic images indicate that all the five samples are spherical in shape AC electrical measurements were carried out on pelletized samples by the parallel plate capacitor method at various temperatures ranging from 40-130 o C and frequencies ranging from 100 Hz -1 MHz Results indicate low AC electrical conductivities and consequently show the occurrence of nano confined states The exciton Bohr radii obtained from the dielectric constant values at 40 o C temperature and 1 kHz frequency are 418, 548, 553, 563 and 270 respectively for the asprepared sample and samples calcined at 400, 500, 600 and 700 o C which indicate a strong quantum confinement effect The
7 citations