First-Principles Study of the Doping of InAs Nanowires: Role of Surface Dangling Bonds

• Published in: Journal of physical chemistry. C 2011-08, Vol.115 (30), p.14449-14454
• Main Authors: Shu, Haibo, Chen, Xiaoshuang, Ding, Zongling, Dong, Ruibing, Lu, Wei
• Format: Article
• Language: English
• Subjects: C: Nanops and Nanostructures
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp112002n

The effect of surface dangling bonds (SDBs) on the doping of InAs nanowires is investigated by first-principles calculations within density functional theory. The result of the formation energies shows that the dangling bonds of In atom on the surface of nanowires are a kind of stable defect. Moreover, the surface dangling bonds prefer to be charged and form trap centers of carriers. For the ultrathin nanowires, both the positively and negatively charged SDBs can be produced. With the increase of size, the stable energy region of the negatively charged SDBs has diminished gradually and disappeared, but the positively charged SDBs keep a high stability. The result originates from the quantum confinement effect that makes stronger influence on the conduction band than the valence band of InAs nanowires. The higher stability of the positively charged SDBs means that the SDBs have an ability to capture the holes from the p-type dopants, resulting in the deactivation of dopants. Thus, the SDBs could be fundamental obstacles for the p-type doping of InAs nanowires. On the basis of our results, the surface passivation can be considered as an effective way to suppress the effect of SDBs on the doping of InAs nanowires.