White luminescence from Si+ and C+ ion-implanted SiO2 films

Abstract

The microstructural and optical analysis of SiO 2 layers emitting white luminescence is reported. These structures have been synthesized by sequential Si ϩ and C ϩ ion implantation and high-temperature annealing. Their white emission results from the presence of up to three bands in the photoluminescence ͑PL͒ spectra, covering the whole visible spectral range. The microstructural characterization reveals the presence of a complex multilayer structure: Si nanocrystals are only observed outside the main C-implanted peak region, with a lower density closer to the surface, being also smaller in size. This lack of uniformity in their density has been related to the inhibiting role of C in their growth dynamics. These nanocrystals are responsible for the band appearing in the red region of the PL spectrum. The analysis of the thermal evolution of the red PL band and its behavior after hydrogenation shows that carbon implantation also prevents the formation of well passivated Si/SiO 2 interfaces. On the other hand, the PL bands appearing at higher energies show the existence of two different characteristics as a function of the implanted dose. For excess atomic concentrations below or equal to 10%, the spectra show a PL band in the blue region. At higher doses, two bands dominate the green-blue spectral region. The evolution of these bands with the implanted dose and annealing time suggests that they are related to the formation of carbon-rich precipitates in the implanted region. Moreover, PL versus depth measurements provide a direct correlation of the green band with the carbon-implanted profile. These PL bands have been assigned to two distinct amorphous phases, with a composition close to elemental graphitic carbon or stoichiometric SiC.

Charge transport along luminescent oxide layers containing Si and SiC nanoparticles

“…The opening of the gap of silicon due to quantum confinement has allowed to observe photoluminescence (PL) in the red-infrared spectral region [6]. The emission energy may vary, depending on one hand on the matrix composition, mostly silicon oxide [7,8], also nitride [9] and oxycarbide [10], on the other hand by the incorporation of other elements in the Si-nc like C [11]. In particular, we have previously shown that the use of alternative nanoparticles with different chemical composition may be a viable method to obtain emission in the visible spectrum, in particular by co-implanting silicon-rich silicon oxide (SRSO) with carbon [11,12].…”

“…The emission energy may vary, depending on one hand on the matrix composition, mostly silicon oxide [7,8], also nitride [9] and oxycarbide [10], on the other hand by the incorporation of other elements in the Si-nc like C [11]. In particular, we have previously shown that the use of alternative nanoparticles with different chemical composition may be a viable method to obtain emission in the visible spectrum, in particular by co-implanting silicon-rich silicon oxide (SRSO) with carbon [11,12]. In this latter case, the processed structures show a white PL consisting in different bands: one in the red-infrared region attributed to the Si-nc, and two other bands, located in the blue or the green, assigned to the formation of SiC compounds or C graphitic-like aggregates, respectively.…”

Polarization strategies to improve the emission of Si-based light sources emitting at 1.55 μm

“…Silicon based light sources have been widely investigated for their implementation in integrated photonic circuits [1][2][3][4][5][6][7][8].…”

Investigation of microstructure modification of C-doped a-SiO2/Si after Pb-ion irradiation

“…For instance, Cu [1], Ge [2, 3], Si [4,5], or C [6] ions implanted into amorphous SiO 2 (a-SiO 2 ) could be used in the synthesis of ultra fine clusters that can show unique electrical and optical properties. In recent years, swift heavy ion irradiations have also been used to investigate the modification of silicon-based materials, and various phenomena such as swift heavy ion irradiations induced blue-violet photoluminescence (PL) [7][8][9] and new chemical bonds formations [10] in C-doped a-SiO 2 were reported. However, data on micro-structure modifications and the relationships between the PL properties and new structures is still scarce.…”