氮化碳晶体的研究进展

Progress in the synthesis and characterization of carbon nitride crystals

介绍了氮化碳晶体的合成与表征研究进展,分析了氮化碳晶体合成中存在的主要困难。分析表明:现有的研究结果还没有给出氮化碳晶体合成的确信证据。高温高压法的主要困难在于反应前驱体的选择与制备以及在高压过程中对热力学参数进行有效地控制;等离子体化学气相沉积中,基体原子,主要是硅原子对氮化碳晶体的合成有很大的影响,但目前缺少这方面的系统研究。反应溅射合成时需要解决的困难是在保持较低基片温度的同时如何提高反应气氛中的N原子含量,寻求高比例的sp3C─N单键的合成条件。电化学方法利用了前驱体中的碳氮单键,能够有效地降低反应能垒和沉积温度,需要解决的问题是如何促进合成产物的晶化和减少副产物。综合运用多种合成技术如在较低的基片温度下,在氮等离子体中通过溅射含有碳氮单键的有机前驱体而引入大量的碳氮单键,控制硅原子在氮化碳晶体生长中的影响程度将是今后氮化碳晶体合成研究的有效途径。

Progress and key difficulties in the synthesis and characterization of carbon nitride crystals are summarized. It could be concluded that there is no definite evidence and effective method for synthesizing a carbon nitride crystal. The main problems in the high temperature and high pressure method are the choice and preparation of the precursor materials and the effective control of thermodynamic parameters during the high pressure processing. For the plasma CVD method, the substrate atom, especially silicon, plays an important role in the synthesis of a carbon nitride crystal. The difficulties needed to be resolved using the ion beam sputtering method are how to increase nitrogen concentration in the reactants at a lower substrate temperature and to find synthesis conditions to form a high concentration of sp^3C-N single bonds. Electrochemical methods can effectively reduce the activation energy and deposition temperature by using precursors containing C-N single bonds, but the problems are how to promote crystallization of the deposits and to decrease the amount of by-products. Combined application of the above mentioned methods may be effective in the synthesis of carbon nitride crystals.