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Raman spectra of Cu2O nanowires


Introduction
 

Cuprous oxide is bright red powder, which almost insoluble in water, and can be converted into divalent copper in acidic solution. It is an important P-type semiconductor with a band gap of only 2.1 eV and a photoelectric conversion efficiency of 18%. In 1998, cuprous oxide was proved to be a promising photocatalyst for the decomposition of water into hydrogen and oxygen under sunlight. Nowadays, with the development of nanomaterials, scientist not only prepared cuprous oxide nanostructures of various sizes and morphologies, but also proposed a variety of morphology control theories, such as quantum dots, nanowires, nanosheets, nanospheres, polyhedrons, hollow structures, etc. Nano Cu2O has been widely used in photoelectric conversion, industrial catalysis and gas sensors as its unique optical and magnetic properties.

 

Raman spectroscopy is to obtain the information of molecular vibration and rotation by scatting light. It is often used for quantitative and qualitative analysis of the structure and composition of substances. In recent years, Raman spectroscopy has been applied to the nondestructive detection and identification of cultural relics. Through the Raman spectra of materials, we can understand the chemical bond, crystallization degree, lattice distortion, phase transition and other information inside the crystal. This paper mainly analyzes the influence of doping on Raman spectra of cuprous oxide.

 

Theory
 

The photoelectric experiments show that doping can improve the photoelectric conversion performance of Cu2O nanotube array electrode. Therefore, this paper mainly analyzes the Raman spectrum characteristics of Cu2O nanowire doped with composites made of semiconductor material Zn.

 


Cuprous oxide is a cubic lattice. Each cell contains two cuprous oxide molecules, as shown in the Fig.1-4.

 

Theoretically, the perfect cuprous oxide crystal of hematite type has Raman activity in six vibration modes. In fact, due to the existence of defects, not only the intensity of the intrinsic peak may be very low or even masked, but also the vibration mode of non-Raman activity can be excited. Different structure and state of cuprous oxide can show different Raman spectrum characteristics.

 

Raman spectroscopic analysis of Cu2O nanowires

Experimental equipment and parameters

Experimental equipment: Finder Vista micro confocal Raman spectrometer system; The laser wavelength is 532nm;

The structure of Cu2O nanowires is shown in the figure below:

Raman spectroscopy analysis

The Raman results are as follows:

According to the Raman spectra of Cu2O nanowires, the strong Raman peaks of Cu2O nanowires are located at 45,65,513 and 1044cm-1, and there are also Raman peaks at 150, 224, 438, 738, 903 and 945 cm-1.The peaks at 150, 227, 513, 903 cm-1 belongs to the Raman spectra of Cu2O nanowires.The peaks at 437 cm-1 belongs to the Raman spectra of ZnO ,so it can be inferred that ZnO was formed.

Conclusion

Compared with micron-level materials, nano-multilevel cuprous oxide exhibits novel and unique Raman optical properties due to the significant defects of its microstructure and the surface reconstruction of the macrostructure. The crystal structure change caused by the size change has a great influence on the change of the internal vibration mode of the crystal. These results can guide archaeologists to obtain more accurate results to identify the cultural relics.