Studies of Fabrication,Structure and Properties of p-n Junction by Electrodepositing Cu2O:Mn on Transparent Conductive Glass Substrates

• Main Authors: Yung-I Lu, 盧永益
• Other Authors: Fu-Yung Hsu
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/12501713013457364254

碩士 === 明志科技大學 === 化工與材料工程研究所 === 98 === In this research、p-n junction was prepared by electrodeposion method. Cuprous oxide with or without Mn-dopant was electroplated on the Sn-doped In2O3 (ITO) and F-doped SnO2 (FTO) glasses. The properties of the fabricated p-n junctions were measured and fully studied. Both ITO and FTO glass substrates are commercial products. All experiments were performed with a potentiostat/galvanostate. A typical electrochemical three electrode configuration was carried out in this study. The ITO- or FTO-glass and copper plate (99.999%) were placed parallel to each other and used as the working and counter electrodes、respectively. An Ag/AgCl with satuated KCl solution was used as the reference electrode. Both constant voltage method and constant current method were used for experiments. The film was electroplated in the water solution、which consists of CuSO4 64 gram and lactic acid 200 ml in one liter. The pH value of the electrolyte was adjusted to 9 to 11 by adding NaOH for different experiments. The MnSO4 was added in the electrolyte to fabricate Mn-doped cuprous oxides. The amounts of MnSO4 added are 0.5、1.0、1.5 and 2.0 gram for different experiments. The electroplating potential was controlled between -0.1 and 0.08 voltage、and the current density 2 mA/cm2 and 5 mA/cm2 . The temperature of the electrolyte was kept constent of 70 ℃. Three different electrolyte solutions、the solutions for Cu2O、Cu2O：Mn (0.17 gram) and Cu2O：Mn (0.34 gram)、were measured and analyzed by inductively coupled plasma (ICP) after each time of electrodeposition. The results revealed that decreasing of the Mn-ions content in the solution was undetectable. X-ray diffraction method was used for the crystal structural analysis. Most the electrodeposited films are preferred orientated. At lower potential voltage or lower current density、the preferred orientation was mainly (200). When potential voltage or current density increased、the the preferred orientation turned from (200) to (111). The surface topography was measured by atomic force microscope (AFM)、the roughness increased with increasing pH values、potential voltages and current densities. The microstructure was studied in the transmission electron microscope. At low electroplated current density、cryatals were equiaxed with twin structure. However、the crystals were columnar at high current density. A UV-Vis.-IR spectrometer was utilized for measurement of transmittance、reflection and absorption of Mn-doped cuprous oxide on the ITO or FTO glass substrate. Energy gaps were then calculated. According to different parameters、the energy gaps are between 2.2 eV and 2.6 eV for different electroplating parameters. The resistivities were measured by the I-V curve measurement. Results showed part of the samples showed good rectification characteristic. In this research、the results have not yet enough to correlate the fabricating parameters and the rectification characteristic.