氮流量对掺氮氧化亚铜薄膜性能的影响

Effect of nitrogen flow rate on the properties of nitrogen-doped Cu2O

氧化亚铜在光伏及光催化等领域有潜在应用,掺氮能增加其空穴浓度从而提高电导率,但氮在氧化亚铜的状态仍未被深入研究.在溅射压强等参数不变的条件下,逐步增加氮气流量,制备了一系列纯相的氮掺杂的氧化亚铜,并用X射线衍射、台阶仪、扫描电子显微镜、能量色散谱仪、拉曼光谱、X射线光电子能谱仪、霍尔效应及分光光度计等方法对所得样品进行分析.霍尔效应测试结果表明,氮掺杂能使氧化亚铜薄膜空穴浓度提高1个数量级.禁带宽度随氮气流量的增加而逐渐减小,氮在氧化亚铜中以β-N(氮原子)、α-N 2(分子态氮,—N N—)及γ-N 2(分子态氮,N≡N)3种形式存在,随着氮流量的增加,β-N的结合能的峰强不断增强,而α-N 2的结合能的峰强不断减弱.氮流量为2标准立方厘米每分钟(sccm)时所得样品的电阻率最小.

Cuprous oxide(Cu 2O)has the potential applications in photovoltaic and photocatalytic fields.Nitrogen-doping in Cu 2O can improve the conductivity by increasing hole concentration.However,the chemical states of nitrogen in nitrogen-doped Cu 2O have not been studied thoroughly.A series of nitrogen-doped Cu 2O samples are prepared by increasing nitrogen flow rates and simultaneously keeping the sputtering pressure and other parameters unchanged.The samples are characterized by X-ray diffraction(XRD),step instrument,scanning electron microscope(SEM),energy dispersive spectrometer,Raman spectroscopy,X-ray photoelectron spectroscopy(XPS),spectrophotometer and Hall effect et al.The results of Hall effect measurement show that nitrogen-doping can increase the hole concentration by one order of magnitude.The band gap width decreases with the increase of nitrogen flow rate.The nitrogen in Cu 2O is in three forms:β-N(nitrogen atom),α-N 2(molecular nitrogen,—N N—)andγ-N 2(molecular nitrogen,N≡N).With the increase of nitrogen gas flow rate,the peak of binding energy ofβ-N increases while that ofα-N 2 decreases.The sample prepared at the nitrogen flow rate of 2.0 sccm has the minimum resistivity among all samples.