Indirect-to-direct band gap transitions in phosphorus adsorbed 〈 112 〉 silicon nanowires

Using first-principles calculations, we investigated the modification of the band structures of 〈 112 〉 silicon nanowires (SiNWs) that were adsorbed with phosphorus atoms. We found that the phosphorus atom adsorption on the (110) and (111) facets causes considerable modifications in the conduction bands. Interestingly, the modifications result in the indirect band gap characteristic enhancement for the adsorption on the (110) facet and induce an indirect-to-direct band gap transition for the adsorption on the (111) facet due to the distribution of the local density of states that are parallel to the (110) facet. The finding has significant implications for SiNWs in optoelectronic applications. © 2008 American Institute of Physics.