Stability and Segregation of B and P Dopants in Si/SiO2 Core鈥揝hell Nanowires
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- 作者：Sunghyun Kim ; Ji-Sang Park ; K. J. Chang
- 刊名：Nano Letters
- 出版年：2012
- 出版时间：October 10, 2012
- 年：2012
- 卷：12
- 期：10
- 页码：5068-5073
- 全文大小：433K
- 年卷期：v.12,no.10(October 10, 2012)
- ISSN：1530-6992
文摘
Using molecular dynamics simulations, we generate realistic atomic models for oxidized Si nanowires which consist of a crystalline Si core and an amorphous SiO2 shell. The amorphous characteristics of SiO2 are well reproduced, as compared to those for bulk amorphous silica. Based on first-principles density functional calculations, we investigate the stability and segregation of B and P dopants near the radial interface between Si and SiO2. Although substitutional B atoms are more stable in the core than in the oxide, B dopants can segregate to the oxide with the aid of Si self-interstitials which are generated during thermal oxidation. The segregation of B dopants occurs in the form of B interstitials in the oxide, leaving the self-interstitials in the Si core. In the case of P dopants, dopant segregation to the oxide is unfavorable even in the presence of self-interstitials. Instead, we find that P dopants tend to aggregate in the Si region near the interface and may form nearest-neighbor donor pairs, which are energetically more stable than isolated P dopants.