Influence of swift heavy ion irradiation on the photoluminescence of Si-nanoparticles and defects in SiO₂

Abstract

The influence of swift heavy ion (SHI) irradiation on the photoluminescence (PL) of silicon nanoparticles (SiNPs) and defects in SiO-film is investigated. SiNPs were formed by implantation of 70 keV Si and subsequent thermal annealing to produce optically active SiNPs and to remove implantation-induced defects. Seven different ion species with energy between 3-36 MeV and fluence from 10-10 cm were employed for irradiation of the implanted samples prior to the thermal annealing. Induced changes in defect and SiNP PL were characterized and correlated with the specific energy loss of the employed SHIs. We find that SHI irradiation, performed before the thermal annealing process, affects both defect and SiNP PL. The change of defect and SiNP PL due to SHI irradiation is found to show a threshold-like behaviour with respect to the electronic stopping power, where a decrease in defect PL and an anticorrelated increase in SiNP PL after the subsequent thermal annealing are observed for electronic stopping exceeding 3-5 keV nm. PL intensities are also compared as a function of total energy deposition and nuclear energy loss. The observed effects can be explained by ion track formation as well as a different type of annealing mechanisms active for SHI irradiation compared to the thermal annealing.

Ag nanoparticles embedded in Nd:YAG crystals irradiated with tilted beam of 200 MeV Xe ions: optical dichroism correlated to particle reshaping

“…Most of the energetic Xe 18+ ions stopped at a depth range of 8-10 μm, resulting in the increase of nuclear stopping power S n due to elastic collision. It is well known that the electronic stopping power S e plays a main role in SHII process [31], which is in agreement with the calculated S n and S e in figure 1(c). Besides, the DPA distribution meets the color changes in the optical microscopy image of figure 1(a), which demonstrates the refractive index variation and lattice damage during SHII.…”

Ion beam tools for nondestructive in-situ and in-operando composition analysis and modification of materials at the Tandem Laboratory in Uppsala

“…When operation of the present pelletron accelerator began in 2001, the MeV-ion irradiation beamline described in [42] was transferred to the facility. Since then it has been employed for various irradiation experiments investigating, for example, defects, vacancies and ion tracks in Si, SiO 2 and SiC [43][44][45], and the effect of heavy ion irradiation on the photoluminescence of Si nanoparticles [46,47]. During irradiation experiments the ion beam delivered by the tandem accelerator is scanned homogenously over an area up to 10 × 10 cm 2 on the target, and ion fluences up to a few times 10 16 cm −2 are readily achievable within hours of exposure time, depending on the selected projectile species.…”