Optical and structural properties of Si nanocrystals produced by Si hot implantation

Abstract

It was already demonstrated that Si hot implantation followed by high-temperature annealing induces the formation of Si nanocrystals ͑Si NCs͒ which when excited in a linear excitation regime present two photoluminescence ͑PL͒ bands ͑at 780 and 1000 nm͒. We have undertaken the present work in order to investigate three features: First, to determine the origin of each band. With this aim we have changed the implantation fluence and the high-temperature annealing time. Second, to investigate the influence of the postannealing atmosphere on the PL recovering process after bombarding the Si NCs. Third, we have annealed the as-produced Si NCs in a forming gas ͑FG͒ atmosphere in order to observe the PL behavior of each band. The results have shown that the 780 nm PL band has its origin in radiative interfacial states, while the 1000 nm one is due to quantum size effects. From the experiments we have concluded that the PL recovery after the Si NCs irradiation strongly depends on the type of postannealing atmosphere. Finally, it was found that the FG treatment strongly affects the line shape of the PL spectrum.

Single layer of silicon quantum dots in silicon oxide matrix: Investigation of forming gas hydrogenation on photoluminescence properties and study of the composition of silicon rich oxide layers

“…Therefore, the PL of these structures relies entirely on the quantum confinement effect of Si QDs. This conclusion is not general and might be invalid for the structures realized using different deposition techniques [20][21][22]. The discrepancy between data presented here and theoretical calculations, shown in Fig.…”

“…These specimens should have a higher defect density compared to the annealed specimens. Other authors have observed high energy PL signals on as-deposited samples realized by ion implantation of Si in SiO 2 [21,22]. In this case PL could be attributed to matrix defects caused by ion-implantation damage.…”

“…It is widely accepted that forming gas (FG) passivates dangling bonds eliminating PL due to interface defects [19], but results are still controversial [6,11,[20][21][22]. In this work the PL of single layer QD structures has been measured, before and after FG posthydrogenation, in order to clarify the emission mechanism of sputtered Si QDs in SiO 2 structures.…”

Formation of Si nanocrystals in ion implanted Si-SiO2structures by MeV electron irradiation

“…The most important property of these nanocrystals is the intense photoluminescence in the visible and the red/near-infrared ranges of the optical spectrum [2,3]. This is why Si nanocrystals are potential candidates for Si-based optoelectronic devices.…”

“…Silicon nanocrystals generated in a SiO 2 matrix have attracted considerable interest due to their excellent optical and electronic properties [1][2]. The most important property of these nanocrystals is the intense photoluminescence in the visible and the red/near-infrared ranges of the optical spectrum [2,3].…”