Potential well

About: Potential well is a research topic. Over the lifetime, 1430 publications have been published within this topic receiving 30812 citations.

Germanium quantum dots formed by oxidation of SiGe alloys

Abstract: We report the investigation on the oxidation behavior of Si 1-x Ge x alloys (x=0.05, 0.15, and 0.25). In the PL spectra of Germanium quantum dots formed by the oxidation of Si 1-x Ge x substrate, at high oxidation temperature (800℃—1000℃) an emission band from 550nm to 720nm would originate from the diameter distribution of germanium nanoparticles (Ge clusters diameter: 3nm—4nm); and at low oxidation temperature (400℃—600℃) with Laser beam radiation, there is an emission band from 650nm to 900nm which may have come from the germanium clusters (diameter: 4nm—5nm). It is clearly seen that there are several peaks at 572nm, 620nm, 671nm, 724nm, 769nm, 810nm and 861nm wavelengths along the emission band, which are correlated to the quantum confinement effect with 3.32nm, 3.54nm, 3.76nm, 3.98nm, 4.17nm, 4.35nm and 4.62nm diameters of the germanium clusters, respectively. The simulation result with MC method demonstrates that the germanium clusters of the above diameters are more stable under the above conditions. A quantum confinement model has been set up, and calculations with the UHFR method and the quantum confinement analysis have been proposed to explain the PL spectra.

Preparation for ZnO quantum dot

Abstract: The present invention provides a preparing method of ZnO quantum dot Firstly, processing surface treatment to a substrate, then forming a layer nano-sphere assembled by itself by czochralski method in deionized water, the nano-sphere is used as a template for preparing ZnO quantum dot; further, depositing a layer ZnO film which thickness is 5nm-50nm by electron beam evaporation under the conditions of temperature between 25-100 DEG C, 10 -10 Torr vacuum; finally, dipping in toluol, and vibrating 2-5 min by ultrasonic to remove the nano-sphere in the template The ZnO quantum dot prepared by the method has large growth area, regular arrangement, even distribution The preparing method simply, economically and effectively produces ZnO quantum dot having larger range, and order The ZnO oxide semiconductor energy gap is wide, direct wide band gap is transmitted, and exciton binding energy is large, the ZnO quantum dot material becomes expectations of high quantum dot laser and nan0-laser by adding the quantum confinement effect of the quantum dot

Studies of hypro-mellose (HPMC) functionalized ZnS:Mn fluorescent quantum dots

Abstract: Fluorescent ZnS:Mn quantum dots coated with hypro-mellose (HPMC) were synthesized by using simple and facile chemical precipitation technique in which HPMC acts as a novel organic surfactant to passivate the surface, to tune the optical properties and also to functionalize the surface of quantum dot for a futuristic controlled drug release applications. Morphological and optical characterizations were done to see the effect of HPMC coating on ZnS:Mn quantum dots. Structural and morphological studies was done by using XRD and TEM respectively. XRD studies confirms the pure zinc blende phase for all the samples. TEM studies shows that HPMC is efficiently doing the surface passivation in doped quantum dots. Optical studies were done by using UV–visible, FTIR and time resolved photoluminescence. UV–visible studies shows that quantum confinement effect is more prominent and also tunable in case of HPMC coated manganese doped ZnS quantum dots. FTIR studies confirms the functionalization of HPMC on the surface of doped ZnS quantum dots. Laser induced time resolved photoluminescence studies were also done to see the effect of HPMC on the photoluminescence intensity of doped quantum dots. Time resolved studies clearly shows the much desired luminescence stability of the HPMC coated quantum dots. It is observed that both the structural and optical characteristics have strong dependence on capping concentration. As HPMC is a very important viscoelastic polymer and organic surfactant used in various types of drug formulations, these studies opens a new way in the area of efficient drug delivery, controlled drug release and targeting.