Preparation And Properties Of ZnO Nanorods Grown By Pulsed Laser Deposition

Zinc Oxide (ZnO) is a new generation of II-VI compound semiconductor with a wide and direct band gap (3.37eV at room temperature) and the high exciton binding energy of 60 MeV. ZnO has a wurtzite crystal structure, low dielectric constant and high chemical stability, optoelectronic and piezoelectric properties. ZnO nanostructures show great promising applications in optoelectronic devices, surface acoustic wave devices, piezoelectricity materials, field emitters, sensors, ultraviolet lasers, solar cells and so on.In this thesis, a PLD system was used for preparation of high-quality ZnO thin films and nanorods on Si(100) substrates. The thesis engaged in the research work of the influences of different growth conditions (the substrate temperature, the single pulse energy, the repeat frequency, the growth time) on feature of ZnO films in four aspects. Structural characteristics grown on Si was studied by measurements of X-ray diffraction(XRD). The microstructures of ZnO films have been investigated by atomic force microscope(AFM) and scan electron miroscope(SEM). The optical properities of ZnO nanorods have been investigated by photoluminescence(PL) spectra.The results showed that the crystal structure and the orientation and the surface morphology and the optical properity of ZnO thin films and ZnO nanorods were affected significantly by growth conditions. During the changing of substrate temperature, at 500℃, ZnO film grown on Si(100) substrates is double deck structure; At 600℃. ZnO film grown on Si(100) substrates is nanorod structure; At 700℃, ZnO film grown on Si(100) substrates is columnar structure. The sizes of grains are influenced by the pulse energy, the repetition rate and the growth time. Room-temperature photoluminescence spectra of the ZnO samples show a strong V-UV emission as well as a blue-green emission.All in all, the researches on ZnO nanorods in the thesis make effort in the optoelectronic fields of the development and applications.