Authors’ contributions RGG carried out the sample preparation, participated on its analysis, performed all the analyses except AFM and FTIR analyses, and wrote the paper. NTH also wrote the paper and analyzed the samples. JC performed the FTIR analysis. QRZ
participated on the AFM analysis and proof corrections. ZY, YJS, LYZ, and YFZ participated in the study guidance and paper correction. All authors read and approved the final manuscript.”
“Background Since the discovery of efficient visible photoluminescence (PL) of silicon nanoparticles (Si-np) due to quantum confinement effects (QCE) , the possibility selleck screening library of bandgap engineering of Si-based materials through the Si-np size control makes Si-based nanostructured material attracting for future applications in optoelectronics as low-cost, miniaturized, and CMOS-compatible, light-emitting devices (LEDs), laser, as well as photovoltaic devices. In the past, researches were focused on luminescent Si-np embedded in Si oxide media. However, the insulating nature of Si oxide remains a barrier for the production of future electrically pumped LEDs and efficient photovoltaic cells. This detrimental aspect can be overcomed to an extent, using a KU-57788 purchase higher conductive host medium like Si nitride which has a lower bandgap energy than SiO2. The first results on Si nitride are promising since many researchers
have reported on efficient visible PL with tunable light emission via the change of the Si nitride composition. However, it also turns out that selleck N-rich nitride [2–4] and Si-rich nitride thin Metalloexopeptidase films containing amorphous [5–8] or crystalline [9–14]
Si-np or without Si-np [15–18] can exhibit PL in the same spectral range. As a result, the mechanism of the PL in Si nitride is still a controversial subject in the literature. QCE in amorphous or crystalline Si-np, defect states in the bandgap, and band tail recombination have been proposed to account for the PL. However, since the synthesis methods were mostly based on chemical vapor deposition techniques, most of the films contained a significant amount of hydrogen [2, 5, 8, 10, 11, 13, 14, 16] and, in some cases, of oxygen [19, 20], which can both contribute to the PL. Consequently, it is difficult to experimentally distinguish the mechanisms of the PL. Then, this article is significant since we report on the structural and optical properties of Si-rich SiN x<1.33 thin films devoid of hydrogen and oxygen. The films were deposited by radio frequency (RF) magnetron sputtering. The excess of Si incorporated during the sputtering process makes possible the formation of Si-np during a suitable annealing. The microstructural properties of the films with regard to the composition and the annealing temperature are investigated. The possible contributions of the Si nitride medium and of Si-np formed during thermal annealing, or laser annealing, on the origin of the PL are discussed notably as a function of the Si-np phase (crystalline or amorphous).