β-SiC(001)晶面小分子吸附的第一性原理研究

Characteristics of molecule absorbed on (001) surface of β-SiC with first principle

采用平面波展开和第一原理赝势法对理想β-SiC(001)Si面晶体及可能吸附的H2、N_2、O_2、CO小分子的超晶胞进行计算。结果发现:当模拟条件为0 K且忽略原子驰豫时,以替位式吸附占据晶格位置时,除N_2外,其他小分子均可吸附在β-SiC(001)的Si表面,且随吸附位置的改变,小分子键长均会发生改变,其中O_2形变最大;从吸附能量角度来看,O_2在β-SiC(001)Si表面的吸附能力最强,其次是H_2,最后是CO。

Based on the first-principles pseudopotentials and the plane wave energy band method, the （001） face of Si in perfect crystal β-SIC and that with the adsorptive molecule H2, N2, O5 and CO were calculated separately. The results show that with ignoring the atomic relaxations and the temperature keeping at 0 K, when the molecule replaces the crystal lattice location, the molecules except N2, can be adsorbed on the Si atoms face of （001） in β-SIC crystal model, meanwhile all the bond distance of molecule changes because of the molecules＇ location difference and the max variation molecule belongs to O2. Based on the energy of adsorption, the easiest adsorbed molecule is O5 and then the H2 and CO molecule.