| Sensors have become integrated into control system, for either mechanical, optical, chemical, or biological applications. The new materials for the sensor designing, diluted magnetic semiconductors (DMS), are attractive candidates which consist of a traditional III-V, II-VI, or group IV semiconductor. Among these DMS materials, manganese Mn-doped GaN (MnxGa1-xN) epitaxial films gain growing interests due to its unique magnetic, optical and chemical properties for control system intelligence sensor design. MnGaN films have been used in spintronic device applications according to its magnetic characterizations, and constructed MnGaN electrodes are of potential material for potentionmetric sensor applications since they have good performance as ion selective electrodes. Moreover, the lattice vibrations and dielectric functions of the MnxGa1-x N films not only provide basic physical properties, but are also unique in their semiconductors electronic functionality: electrical and magnetic properties which allow control of electron spin as well as charge flow, making the materials ideal for spintronic applications.;In this work, the Metal-Organic Chemical Vapour Deposition (MOCVD) epitaxial film MnGaN has been examined by Secondary Electron Emission (SEM), Energy Dispersive X-ray Spectrometer (EDS), X-Ray Diffraction (XRD), Ultraviolet (UV) measurements, and Open Circuit Potential (OCP) for its crystalline quality and surface structure, optical characterization, and electrochemical properties.;The surface structure of MnxGa1-xN epitaxial films are discovered by SEM images. It found that the Mn atoms concentrated at one region of the film. The perfect crystal structure, magnetic properties and distribution of elements are clearly discussed and demonstrated by high resolution XRD and EDS measurements, which also provide the practical data for the relative calculation. Moreover, optical characterizations, for example, the energy band gap of MnGaN changes in the range 1.9eV-3.5eV, are revealed by the UV measurements. It is a great discovery for semiconductor nanotechnology of a traditional III-V, II-VI, or group IV semiconductor.;The electrochemical properties of MnxGa1-xN thin films are for the first time presented by Ion Selective Electrodes (ISE). This thesis demonstrates the potential use of MnGaN semiconductor as an all solid-state potentiometric sensor for measuring anions in solutions of the control engineering field. The sample electrodes showed good sensitivity of Cl-, Br-, I-, and ClO4 - comparing all tested organic and inorganic anions.;Although studies on the magnetic properties of MnxGa 1-xN are widely available, there are only a few studies on the optical properties and electrochemical properties of MnxGa1-xN epitaxial films. Designing such spintronic and opto-electronic devices based on MnxGa1-xN requires a broader understanding of physical, optical, electrical and chemical properties of wurtzite MnxGa 1-xN epitaxial films, which are still rare in the literature. |
