Effect of surface treatment on surface structure and epitaxial growth of Cu2O

• Main Authors: Chih-Yang Hsu, 許智揚
• Other Authors: Liuwen Chang
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/xpdat4

碩士 === 國立中山大學 === 材料與光電科學學系研究所 === 107 === Cuprous oxide(Cu2O) was electrodeposited epitaxially on a polycrystalline copper substrate in galvanostatic condition in copper sulfate solution. The Cu2O films grown on the <100>//ND, <110>//ND and <111>//ND Cu grains were all flat with the root-mean-square roughness value of 5-7 nm according to the scanning electron microscopy(SEM) observation and atomic force microscopy(AFM) measurement. Photoluminescence(PL) analysis at room Temperature showed the epitaxial film generated a sharp near-band emission peak at 2.02 eV, indicating that the films has good optical properties. X-ray photoelectron spectroscopy and Transmission electron microscopy confirmed that the film prepared in this experiment contained copper nanoparticles with cube-on-cube orientation relationship with the Cu2O matrix. X-ray photoelectron spectroscopy showed the surface of the Cu2O film was covered by a thin layer of copper hydroxide, resulting in the broadening of the O1s peak. After heating to 200 °C in a vacuum, the copper hydroxide layer decomposed into nano particles of Cu which spread on the Cu2O surface. The copper hydroxide layer can not be removed by acidic solution, but part or all of the copper hydroxide was removed partly or completely by dipping in diethyl ether or absolute alcohol. Interruption experiment showed that the epitaxial growth of Cu2O was not affected after the hydroxide layer was removed. However, the epitaxial growth was in deed affected significantly by the presence of the Cu nano particle, in this experiment, Magnesium oxide(MgO) film are growth on Cu2O film by molecular beam epitaxy(MBE). The resultant MgO film was polycrystalline.