Influence of phosphorus on the growth and the photoluminescence properties of Si-NCs formed in P-doped SiO/SiO₂ multilayers

Abstract

Localization at the nanoscale and influence of P atoms on optically active Si-NCs embedded in a SiO2 matrix.

Heavily Doped Si Nanocrystals Formed in P-(SiO/SiO2) Multilayers: A Promising Route for Si-Based Infrared Plasmonics

“…They show that the nanoparticles are mainly single crystalline with the Si diamond-like cubic structure. The expected multilayer structure is no longer fully preserved as a result of the P-induced softening of the silica matrix, as already mentioned in a previous work 20 or by the increase of atomic diffusion induced by dopants. 34 The Si-NC size remains, however, limited and almost controlled by the presence of the SiO 2 barrier layers, as shown by the histograms of the size distribution (Figure 2f).…”

“…For the multilayer containing 1.1 atom % of P, the mean P content reaches a value of 10.3 ± 1.1 atom %, i.e., well beyond the solid solubility limit of P in bulk Si (i.e., 6 × 10 20 cm –3 at 1100 °C). As the P content in the multilayers increases from 0.7 to 1.1 atom %, the mean Si-NC size increases from about 5.4 ± 0.1 to 6.5 ± 0.1 nm, which is well explained by the enhanced Si diffusion in the presence of P. , Meanwhile, the P content in the Si-NCs also increases from about 5.6 ± 1.4 to 10.3 ± 1.1 atom % at constant Si-NC size. However, despite the large P contents in the Si-NCs, alloying and formation of SiP nanoparticles are not observed.…”

“…Due to their low cost, compatibility with the CMOS technology, ease of fabrication, and nontoxicity, Si nanocrystals (Si-NCs) appear particularly promising. Although some theoretical works suggested that insertion of dopants at the nanoscale is not favored by thermodynamics, several authors have nevertheless shown that Si-NCs can contain P atoms or B atoms. − Moreover, hyperdoping has emerged as a possible route to generate LSPR in Si-NCs. Using tight-binding calculations, Pi and Delerue have investigated the optical response of hyperdoped Si-NCs.…”

Hyperdoped Si nanocrystals embedded in silica for infrared plasmonics

“…Such concentrations of some at% are consistent with previous studies in the literature, which conclude that doping SiNCs in SiO 2 corresponds to a thermodynamically favorable configuration. 21,22,32,40 The measured P concentrations are indeed up to six times higher than the solid solubility of P in bulk Si at the same temperature (1.8 at%). 41 However, it is impossible to conclude that the observed increase in the incorporated dopant concentration is due to an equilibrium property of SiNCs embedded in SiO 2 described in ref.…”

“…NC growth with P content has previously been reported in the literature for SiNCs prepared in a silica matrix using various techniques. 40,[46][47][48] The size of SiNCs in phosphosilicate glasses is almost independent of the impurity concentration at low P concentrations. The average size of SiNCs in pure SiO 2 with the same Si concentration becomes larger at high P concentrations (e.g., >1 mol percentage).…”