科研之友
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摘要
The structural and electronic properties of amorphous silicon (a-Si) are investigated by first-principles calculations based on the density-functional theory (DFT), focusing on the intrinsic structural defects. By simulated melting and quenching of a crystalline silicon model through the Car-Parrinello molecular dynamics (CPMD), we generate several different a-Si samples, in which three-fold (T-3), five-fold (T-5), and anomalous four-fold (T-4a) defects are contained. Using the samples, we clarify how the disordered structure of a-Si affects the characters of its density of states (DOS). We subsequently study the properties of defect complexes found in the obtained samples, including one that comprises three T-5 defects, and we show the conditions for the defect complexes to be energetically stable. Finally, we investigate the hydrogen passivation process of the T-5 defects in a-Si and show that the hydrogenation of T-5 is an exothermic reaction and that the activation energy for a H-2 molecule to passivate two T-5 sites is calculated to be 1.05 eV.
- 出版日期2017-10-1
