Atomic and electronic properties of P/Si(1 1 1)-(2 × 1) surface

¹ Department of Engineering Physics, Faculty of Engineering, Ankara University, 06100 Ankara, Turkey
² Department of Physics, Gazi University, 06500 Ankara, Turkey

^a e-mail: zaydugan@yahoo.com

Received: 6 April 2011
Revised: 29 July 2011
Accepted: 11 August 2011
Published online: 14 November 2011

Abstract

The atomic and electronic properties of the substitutional phosphorus (P) on the Si(1 1 1)-(2 × 1) surface have been studied by using the ab initio density functional theory (DFT) based on pseudopotential approach. We have considered four different possible binding sites for P adatom in the π-bonded chain labeled sites 1–4 respectively in Figure 1. We have found that the site 1 position in the π-bonded chain was energetically more favorable than the other binding sites, by about 0.1 eV/adatom. We have also calculated the corresponding surface electronic band structure and found one surface state, labeled C, in the fundamental band gap of Si(1 1 1)-(2 × 1) surface. Our calculations show that the P/Si(1 1 1)-(2 × 1) surface has a metallic character in the nature. In order to explain the nature of this surface state in the bonding geometry, we have depicted the total and partial charge density contours plots at the point of the surface Brillouin zone (SBZ).