الفهرس | Only 14 pages are availabe for public view |
Abstract Zinc oxide (ZnO), a member of the II-VI group semiconductors with a direct wide band gap (3.3 eV), a large excitonic binding energy (60 meV) at 300 K and availability of large single crystals, possesses a unique position among materials owing to its superior and diverse properties such as piezoelectricity, chemical stability, biocompatibility, optical transparency in the visible region, high radiation hardness, high voltage current nonlinearity, etc. Also ZnO has a lower threshold voltage for use as a light-emitting diode (LED) and in laser emission, and TM-doped ZnO is predicted to display properties of diluted magnetic semiconductors with ferromagnetic Curie temperature well above 300 K. Thus, ZnO as a multifunctional materials could be used in a range of industrial applications such as transparent electrodes, solar cells, gas sensors, photodiode, transistors, surface acoustic wave devices and for use in spintronics applications. Its low cost compared with other materials makes it a good candidate for industrial applications. Recently, nanostructured ZnO has been obtained by using various physical and chemical techniques. TM-doped ZnO or Zn1-xTMxO thin films were deposited onto glass substrates by the sol–gel method via a spin-coating technique. The dopant ratio x < 10 %. The used transition metal (TM) is copper (Cu) for the first system, chromium (Cr) for the second system, and for the third system, TM is cadmium (Cd). The choice of these systems arises from that they are less investigated; however, they are expected to have excellent optical, electrical, and magnetic properties and could be used in many research, environmental. |