Engineering the Optical and Electrical Conduction Parameters of ZnSe Thin Films via YAu Alloy Nanosandwiching رسالة ماجستير

Abstract

One of the most important challenges that make the visible light communication technology hardly possible is the absence of light converters that perform without altering the properties of the incident light signal. For that reason here in this thesis, we implant an alternating approach for engineering the optical and electrical parameters of ZnSe thin films by the nanosandwiching technique. The work is promising as it indicates the ability of using the nanosandwiched ZnSe in visible light communication and as a microwave resonator. Particularly, two thin layers of yttrium and gold metals are co-evaporated onto a ZnSe thin film. The ZnSe/Y, ZnSe/Au and ZnSe/YAu films are recoated with another ZnSe film to form the nanosandwiched proposed structure. The basic properties of the sandwiched ZnSe are investigated by means of x-ray diffraction, optical spectroscopy and conductance spectroscopy in the measurement domains of 10-70o, 270-1000 THz and 0.01-1.8 GHz, respectively. The effect of the Y, Au and YAu on lattice constant, energy band gap, dielectric constant and optical and electrical the conductivities are explored. In addition, the transient optical and electrical conductivities are modeled by the existing models and theories which concern Drude-Lorentz plasmonic interaction in the terahertz range, the quantum mechanical tunneling and correlated hoping conduction of charge xviii carriers in the frequency range 0.01-1.8 GHz to observe the variations associated with the metal sandwiching process in the optical and electrical conduction parameters like, the density of localized states near the Fermi level, scattering time constant at femtosecond levels and then electron-plasmon interactions. Particularly, an abrupt increase in the free carrier density is observed upon insertion of YAu layers. The increase in the free carrier density is associated which enhancement in the Plasmon frequency which reached ∼4.83 GHz.