Investigation of the electronic structure of the phosphorus‐doped Si and SiO₂:Si quantum dots by XPS and HREELS methods

Abstract

The system of the nanocrystals of Si in the SiO 2 matrix (SiO 2 : Si) attracts a great amount of attention due to its ability for luminescence in the visible and near-IR range of spectrum. The influence of the P ion doping was investigated for the electronic structure of the Si single crystal and the SiO 2 : Si nanocomposite. The P doping of SiO 2 implanted with Si + and post-annealed at T = 1000 • C (2 h) results in the enhancement of the PL peak connected with the Si nanocrystals. Owing to the low concentration of Si nanocrystals in the SiO 2 matrix, the peculiarities of the P influence on the Si electronic structure were investigated on model samples (Si single crystals with ion doping by P). The determination of the chemical state of the P impurity and the electronic structure of the P-doped Si and (SiO 2 : Si) quantum dots was carried out using XPS and high-resolution electron energy loss spectroscopy (HREELS). The experimental density of the states (DOS) in the valence band and conduction band of the SiO 2 : Si composite are in good agreement with the calculation of the local electronic structure around small Si inclusions in the SiO 2 matrix by means of the LMTO (linear muffin-tin orbital) method.

Thermodynamic stability of high phosphorus concentration in silicon nanostructures

“…14, 45 The XPS data demonstrate that, during the annealing process, the diffusing P atoms are trapped in the Si NC region and incorporated in the core of the nanostructure or in a sub-interface region exhibiting no bonds with O atoms. The sensitivity of the XPS measurements does not allow excluding the presence of a residual amount of P in the surrounding SiO 2 matrix.…”

Investigation of electronic structure of Si nanocrystals and their interface with host matrix in P-doped SiO2:Si and Al2O3:Si nanocomposites

“…5b) significantly. As it was shown earlier [1], this etching allowed to reach the subsurface layers with maximal concentration of P and Si. The peaks at 44, 95, 157 and 250 meV are clearly resolved.…”

“…The dispersion of Si particles significantly increases the luminescence of non-direct band semiconductors. It was found earlier that ion doping of the nanocrystalline Si by donor elements gives additional increase of PL and changes its electronic structure [1]. However, up to present time, the influence of doping was investigated insufficiently and present data have discordance.…”

The peculiarities of electronic structure of Si nanocrystals formed in SiO2 and Al2O3 matrix with and without P doping

“…It was established earlier that ion doping of the nanocrystalline Si by donor elements gives an additional increase of PL and changes its electronic structure. 3 The mechanisms of phosphorus influence on PL properties are unknown, although some assumptions were suggested in Refs 4 and 5. The present paper deals with the influence of P doping on the electronic structure and properties of (SiO 2 : Si) and (Al 2 O 3 : Si) nanocomposites and interfaces.…”