HAL (Le Centre pour la Communication Scientifique Directe), Jul 7, 2008
ABSTRACT We have studied the self-organized growth of InAs Quantum dots in an InP on both nominal... more ABSTRACT We have studied the self-organized growth of InAs Quantum dots in an InP on both nominally oriented and vicinal InP(001). Atomic force microscopy demonstrates that the off-cut direction of vicinal substrates – largely dependent of growth conditions – determines the morphology of nanostructures.
Journal of Photochemistry and Photobiology A: Chemistry, 2021
Abstract This work reports the preparation of Carbon Quantum Dots via one-step microwave-assisted... more Abstract This work reports the preparation of Carbon Quantum Dots via one-step microwave-assisted synthesis, to be employed for the determination of Minocycline antibiotic. Linear relationship was observed between photoluminescence quenching of CQDs and Minocycline concentration between 0.28–30.39 μM. UV–vis and PL Spectroscopy revealed that PL decrease arise from Inner Filter Effect. Selectivity studies were conducted to evaluate interference of various compounds on MC detection. In addition, Minocycline was loaded on Chitosan-grafted-oligomeric Lactic Acid microspheres, to be used as a drug carrier of Minocycline. Thereafter, CQDs were used to determine loading capacity, encapsulation efficiency, and cumulative drug release of Minocycline-loaded microspheres. Optimum samples showed loading capacity between 14.1–26.344 %, and encapsulation efficiency between 34.48–64.37%. CHS-g-OLA2 sample showed diminished burst release, and 50 % cumulative drug release during 4 days. Mathematical modelling showed that CHS-g-OLA2 sample follows Higuchi kinetic model, which describes the release of drug from swellable matrix by diffusion.
Silicon monoxide, SiOhas been deposited on Low-Density Polyethylene (LDPE) surface using Physical... more Silicon monoxide, SiOhas been deposited on Low-Density Polyethylene (LDPE) surface using Physical Vapor Deposition (PVD) technique. Several thickness films (200, 500 and 700 nm) were prepared. The obtained films were identified and characterized by Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV-VIS) and atomic force microscopy (AFM). At specific coating thickness, far infrared radiation transmittance was prohibited while the ultraviolet–visible transmittance is allowed and that will be explained in details. AFM results showed homogenous and smooth silicon mono oxide thin films. The mean grain size, average roughness (Ra) and root mean square (RMS) roughness values for SiO films were estimated from AFM. Optical measurements show that the coated films prevent the transmission of IR radiation near 9.5μm and allow UV-VIS transmission during the sun-shining time.
International journal of analytical chemistry, 2017
A micropyramid structure was formed on the surface of a monocrystalline silicon wafer (100) using... more A micropyramid structure was formed on the surface of a monocrystalline silicon wafer (100) using a wet chemical anisotropic etching technique. The main objective was to evaluate the performance of the etchant based on the silicon surface reflectance. Different isopropyl alcohol (IPA) volume concentrations (2, 4, 6, 8, and 10%) and different etching times (10, 20, 30, 40, and 50 min) were selected to study the total reflectance of silicon wafers. The other parameters such as NaOH concentration (12% wt.), the temperature of the solution (81.5°C), and range of stirrer speeds (400 rpm) were kept constant for all processes. The surface morphology of the wafer was analyzed by optical microscopy and atomic force microscopy (AFM). The AFM images confirmed a well-uniform pyramidal structure with various average pyramid sizes ranging from 1 to 1.6 μm. A UV-Vis spectrophotometer with integrating sphere was used to obtain the total reflectivity. The textured silicon wafers show high absorbance...
Theoretical and experimental studies of the electronic properties of InAs(Sb) quantum dots (QDs) ... more Theoretical and experimental studies of the electronic properties of InAs(Sb) quantum dots (QDs) grown by molecular beam epitaxy (MBE) on InP(100) substrate are presented. Eight-band k.p calculations including strain and piezoelectric effects are performed on InAs/InP(100) quantum dot (QD) structure to study the influence of the quantum dot height. Photoluminescence (PL) spectroscopy experiments show promising results. High arsine flow rate
TiO2 photoanodes have gained significant attention for the removal of organic pollutants through ... more TiO2 photoanodes have gained significant attention for the removal of organic pollutants through photoelectrocatalytic processes, with the aim of developing a cost-effective and efficient method for improving the degradation of pollutants in surface water. This study investigated the effects of adding titanium nanooxide (Degussa P25) containing 70% anatase and 30% rutile phases on the properties of nanostructured TiO2 photoanodes prepared on glass substrates (indium tin oxide (ITO)) using sol–gel/dip coating techniques The results obtained from ultraviolet–visible transmittance spectroscopy, electrochemical (EC) impedance spectroscopy, photocurrent, and atomic force microscopy analyses revealed that the addition of Degussa P25 improved the electrical conductivity of the TiO2/ITO anode and reduced the optical bandgap from 3.50 to 3.35 eV, while the size of the titanium oxide particles decreased to about 75 nm. The EC impedance spectra measurement confirms that the addition of titaniu...
HAL (Le Centre pour la Communication Scientifique Directe), Jul 7, 2008
ABSTRACT We have studied the self-organized growth of InAs Quantum dots in an InP on both nominal... more ABSTRACT We have studied the self-organized growth of InAs Quantum dots in an InP on both nominally oriented and vicinal InP(001). Atomic force microscopy demonstrates that the off-cut direction of vicinal substrates – largely dependent of growth conditions – determines the morphology of nanostructures.
Journal of Photochemistry and Photobiology A: Chemistry, 2021
Abstract This work reports the preparation of Carbon Quantum Dots via one-step microwave-assisted... more Abstract This work reports the preparation of Carbon Quantum Dots via one-step microwave-assisted synthesis, to be employed for the determination of Minocycline antibiotic. Linear relationship was observed between photoluminescence quenching of CQDs and Minocycline concentration between 0.28–30.39 μM. UV–vis and PL Spectroscopy revealed that PL decrease arise from Inner Filter Effect. Selectivity studies were conducted to evaluate interference of various compounds on MC detection. In addition, Minocycline was loaded on Chitosan-grafted-oligomeric Lactic Acid microspheres, to be used as a drug carrier of Minocycline. Thereafter, CQDs were used to determine loading capacity, encapsulation efficiency, and cumulative drug release of Minocycline-loaded microspheres. Optimum samples showed loading capacity between 14.1–26.344 %, and encapsulation efficiency between 34.48–64.37%. CHS-g-OLA2 sample showed diminished burst release, and 50 % cumulative drug release during 4 days. Mathematical modelling showed that CHS-g-OLA2 sample follows Higuchi kinetic model, which describes the release of drug from swellable matrix by diffusion.
Silicon monoxide, SiOhas been deposited on Low-Density Polyethylene (LDPE) surface using Physical... more Silicon monoxide, SiOhas been deposited on Low-Density Polyethylene (LDPE) surface using Physical Vapor Deposition (PVD) technique. Several thickness films (200, 500 and 700 nm) were prepared. The obtained films were identified and characterized by Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV-VIS) and atomic force microscopy (AFM). At specific coating thickness, far infrared radiation transmittance was prohibited while the ultraviolet–visible transmittance is allowed and that will be explained in details. AFM results showed homogenous and smooth silicon mono oxide thin films. The mean grain size, average roughness (Ra) and root mean square (RMS) roughness values for SiO films were estimated from AFM. Optical measurements show that the coated films prevent the transmission of IR radiation near 9.5μm and allow UV-VIS transmission during the sun-shining time.
International journal of analytical chemistry, 2017
A micropyramid structure was formed on the surface of a monocrystalline silicon wafer (100) using... more A micropyramid structure was formed on the surface of a monocrystalline silicon wafer (100) using a wet chemical anisotropic etching technique. The main objective was to evaluate the performance of the etchant based on the silicon surface reflectance. Different isopropyl alcohol (IPA) volume concentrations (2, 4, 6, 8, and 10%) and different etching times (10, 20, 30, 40, and 50 min) were selected to study the total reflectance of silicon wafers. The other parameters such as NaOH concentration (12% wt.), the temperature of the solution (81.5°C), and range of stirrer speeds (400 rpm) were kept constant for all processes. The surface morphology of the wafer was analyzed by optical microscopy and atomic force microscopy (AFM). The AFM images confirmed a well-uniform pyramidal structure with various average pyramid sizes ranging from 1 to 1.6 μm. A UV-Vis spectrophotometer with integrating sphere was used to obtain the total reflectivity. The textured silicon wafers show high absorbance...
Theoretical and experimental studies of the electronic properties of InAs(Sb) quantum dots (QDs) ... more Theoretical and experimental studies of the electronic properties of InAs(Sb) quantum dots (QDs) grown by molecular beam epitaxy (MBE) on InP(100) substrate are presented. Eight-band k.p calculations including strain and piezoelectric effects are performed on InAs/InP(100) quantum dot (QD) structure to study the influence of the quantum dot height. Photoluminescence (PL) spectroscopy experiments show promising results. High arsine flow rate
TiO2 photoanodes have gained significant attention for the removal of organic pollutants through ... more TiO2 photoanodes have gained significant attention for the removal of organic pollutants through photoelectrocatalytic processes, with the aim of developing a cost-effective and efficient method for improving the degradation of pollutants in surface water. This study investigated the effects of adding titanium nanooxide (Degussa P25) containing 70% anatase and 30% rutile phases on the properties of nanostructured TiO2 photoanodes prepared on glass substrates (indium tin oxide (ITO)) using sol–gel/dip coating techniques The results obtained from ultraviolet–visible transmittance spectroscopy, electrochemical (EC) impedance spectroscopy, photocurrent, and atomic force microscopy analyses revealed that the addition of Degussa P25 improved the electrical conductivity of the TiO2/ITO anode and reduced the optical bandgap from 3.50 to 3.35 eV, while the size of the titanium oxide particles decreased to about 75 nm. The EC impedance spectra measurement confirms that the addition of titaniu...
Uploads
Papers by Ibrahim M Alghoraibi