2 results
Search Results
Now showing 1 - 2 of 2
Article Citation - WoS: 27Citation - Scopus: 30Effects of Au Nanoslabs on the Performance of Cdo Thin Films Designed for Optoelectronic Applications(Elsevier, 2021) Alharbi, Seham Reef; Qasrawi, A. F.In this work, the effect of 50 nm thick gold nanosheets on the structural, morphological, optical and electrical properties of stacked layers of CdO are investigated. The insertion of Au nanoslabs decreased the lattice parameters of the cubic unit cells of CdO. It also decreased the microstrain, the defect density, the stacking fault percentage and increased the crystallite and grain sizes. Optically, the light absorbability is enhanced, the energy band gap is shrunk and the optical conductivity is increased. The optical conductivity parameters presented by scattering time, plasmon frequency, drift mobility and free carrier density are all engineered via participation of Au nanosheets. On the other hand, electrical measurements in the frequency domain of 0.01-1.80 GHz indicated that the Au nanosheets forced the capacitance spectra to exhibit negative values and increased the electrical conductivity in the studied frequency domain. The terahertz cutoff frequency is tuned in the range of 5.0-22.0 THz indicating the applicability of the CdO/Au/CdO (CAC) films as terahertz filters. The direct current electrical conductivity measurements have shown that while the CC samples exhibit nondegenerate extrinsic nature of conduction, the CAC samples displayed degenerate/nondegenerate transitions at 400 K. With the feature of negative capacitance that can be used for noise reduction and parasitic capacitance cancellation, the CAC films can be regarded as promising structure for multifunctional device applications.Article Citation - WoS: 7Citation - Scopus: 7Enhancing the Optoelectronic Performance of As2se3< Thin Films Via Ag Slabs Sandwiching(Elsevier Gmbh, 2020) Qasrawi, A. F.; Alharbi, Seham ReefIn this work, the effects of insertion of Ag slabs of thicknesses of 50, 100 and 200 nm between layers of arsenic selenide are reported. The glassy structured As2Se3 is characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy, ultraviolet-visible light spectrophotometry and impedance spectroscopy techniques. While the two stacked layers of As2Se3 exhibited high absorption and energy band gap values that nominate them for optoelectronic applications, the Ag slabs enhanced the light absorbability by 3.98, 5.77, 6.13 times and shrunk the energy band gap by 1.16 %, 7.40 % and 13.8 % for Ag slabs of thicknesses of 50, 100 and 200 nm, respectively. In addition, even though the As2Se3/As2Se3 layers exhibited negative capacitance effect in the frequency domain of 0.01-1.80 GHz, the insertion of Ag slabs removed the negative capacitance effect and forced the capacitance spectra to exhibit resonance at critical frequency of value of 0.23 GHz. The modeling of the capacitance spectra have shown that the geometrical capacitance is increased by one order of magnitude upon Ag slabs insertion. The dynamic capacitance is limited by electrons (holes) plasmonic interaction at the interface between the As2Se3/Ag/As2Se3 layers. Furthermore, the capacitance- voltage characteristics of the As2Se3/Ag/As2Se3 films confirmed the suitability of the devices to exhibit MOS device features. The characteristics of the stacked layers of As2Se3 indicate their multi-functionality as an optical absorbers/receivers and as microwave cavities.
