Investigation On Growth And Properties Of Phosphorus Doped ZnO Nanowires And Light Emitting Device

ZnO has attracted widely attention for its wide band gap of3.37eV and relatively large exction binding energy of60meV at room temperature (RT). It has been regarded as one of the most promising material candidates for the next generation of short wavelength optoelectronic devices, especially it has promising potentials in extensive applications and development value for ultraviolet (UV) light emitting diodes (LEDs) and laser devices (LDs). However for the real application of ZnO nanostructures based optoelectronic devices, it is necessary to obtained both n-type and p-type ZnO nanostructures. Unfortunately, ZnO is intrinsically n-type materials and we are easy to get high quality n-type ZnO nano materials, therefore, most efforts have been focused attention to obtain p-type ZnO materials.According to the present research hotspots and difficulties on ZnO, in this thesis we have synthesized high quality n-ZnO nanowires and p-ZnO nanowires by simple chemical vapor deposition method. Meanwhile, phosphorus-doped p-ZnO nanowires/n-ZnO nanowires/n-Si structure homojunction LED was successfully fabricated. The major research achievements are listed below:(1) ZnO nanowires with different phosphorus concentration were grown on Si (111) substrates by chemical vapor deposition method without using catalyst. The surface morphology and structural of ZnO nanowires with different phosphorus concentration were investigated by field-emission scanning electron microscope (FE-SEM) and X-ray diffraction (XRD). With increasing phosphorus concentration, the surface morphology and structural of the ZnO nanowires were impacted and the top of nanowires shown a sharper tip. The phosphorus related acceptor emissions (A0X) were observed from photoluminescence spectra of phosphorus-doped ZnO nanowires at20K.(2) The phosphorus-doped ZnO nanowires/n-ZnO nanowires/n-Si homojunctions were synthesized by simple chemical vapor deposition method. The surface morphology, structural and optical properties of phosphorus-doped p-ZnO nanowires and undoped ZnO nanowires were investigated by field-emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD) and photoluminescence (PL). The Ⅰ-Ⅴ characteristics showed a good rectifying behavior. Furthermore, the electroluminescence spectrum was obtained on the ZnO nanowires homojunctions at room temperature with a weak ultraviolet emission peak at3.18eV and a broad visible band centered at2.39eV. These results further demonstrate the effective p-type conductivity of phosphorus-doped ZnO nanowires.