Ab initio Study of the Effect of Nitrogen on Diamond Film Growth

• Main Authors: Tsung-Che Li, 李宗哲
• Other Authors: Po-Liang Liu
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/cgi-bin/gs32/gsweb.cgi/login?o=dnclcdr&s=id=%22107NCHU5693030%22.&searchmode=basic

碩士 === 國立中興大學 === 精密工程學系所 === 107 === The reaction energy for growing a nitrogen-doped diamond thin film on (100), (110), and (111) orientations by using chemical vapor deposition (CVD) has been studied in this work. The mechanisms involved in CVD include the hydrogen abstruction from diamond surface, methyl molecule adsorption on diamond surface, and hydrogen abstraction from methyl molecule. The result shows that it takes about -0.64 eV and -2.95 eV for hydrogen atoms to abstrate from the surface of undoped and nitrogen-doped diamond (111), respectively. This indicates that the third carbon layer could be easily substituted by nitrogen atoms through the hydrogen abstraction. This behavior is beneficial to the subsequent adsorption of methyl molecule on diamond surface. On the other hand, the energies for methyl molecule adsorption are of -4.66 eV and -2.46 eV, respectively on the surfaces of undoped and nitrogen-doped diamond. This implies that the adsorption of methyl molecule on the nitrogen-doped diamond takes a slightly higher energy than that on the undoped diamond. However, the lowst adsorption energy at -2.46 eV could be obtained while the carbon atoms at second layer of diamond (100) is substituted by the nitrogen atoms. Consequently, the following abstraction of hydrogen from methyl group becomes easier. Likewise, the growth of diamond thin film could be facilitated because of the substitution of carbon atoms at second layer of methyl group by nitrogen atoms through hydrogen abstraction.