Optical properties of an ensemble of G-centers in silicon

Abstract

We addressed the carrier dynamics in so-called G-centers in silicon (consisting of substitutional-interstitial carbon pairs interacting with interstitial silicons) obtained via ion implantation into a silicon-on-insulator wafer. For this point defect in silicon emitting in the telecommunication wavelength range, we unravel the recombination dynamics by time-resolved photoluminescence spectroscopy. More specifically, we performed detailed photoluminescence experiments as a function of excitation energy, incident power, irradiation fluence and temperature in order to study the impact of radiative and non-radiative recombination channels on the spectrum, yield and lifetime of G-centers. The sharp line emitting at 969 meV ($\sim$1280 nm) and the broad asymmetric sideband developing at lower energy share the same recombination dynamics as shown by time-resolved experiments performed selectively on each spectral component. This feature accounts for the common origin of the two emission bands which are unambiguously attributed to the zero-phonon line and to the corresponding phonon sideband. In the framework of the Huang-Rhys theory with non-perturbative calculations, we reach an estimation of 1.6$\pm$0.1 $\angstrom$ for the spatial extension of the electronic wave function in the G-center. The radiative recombination time measured at low temperature lies in the 6 ns-range. The estimation of both radiative and non-radiative recombination rates as a function of temperature further demonstrate a constant radiative lifetime. Finally, although G-centers are shallow levels in silicon, we find a value of the Debye-Waller factor comparable to deep levels in wide-bandgap materials. Our results point out the potential of G-centers as a solid-state light source to be integrated into opto-electronic devices within a common silicon platform

Highly enriched Si28 reveals remarkable optical linewidths and fine structure for well-known damage centers

“…The inhomogeneous isotope broadening inherent to nat Si can be eliminated in 28 Si, resulting in linewidth improvements of over two order of magnitude for the C and G centers. Indeed, the linewidth of the G center components seen in 28 Si are only slightly more than twice the limit imposed by homogeneous lifetime broadening, given the measured 5.9 ns G center lifetime [4]. The improved linewidths in 28 Si allow for the clear observation of distinct isotopeshifted components which are much more difficult to observe in nat Si.…”

“…The G center, with a NP line at ∼969 meV (∼1280 nm) is one of the most studied radiation damage centers in Si due to its extraordinarily bright emission, as well as large oscillator strength as evidenced by strong optical absorption even for relatively low G center concentrations [1]. Beaufils et al [4] provide an up-to-date and comprehensive review of the G center literature, together with new data on temperature dependences, and a precise measurement of the 5.9 ns luminescence decay time. The G center is now widely agreed to consist of a substitutional-interstitial C pair (C i -C s ) coupled to a Si i .…”

“…Here we report on optical emission and absorption studies on three well-known damage centers produced in very high purity Si enriched to 99.995% 28 Si as part of the Avogadro project [12]. All three emit in or near important optical communication bands: the C center (790 meV, or 1571 nm, thought to contain an interstitial C (C i ) and an interstitial O (O i ) [13][14][15][16][17][18]), the G center (969 meV, or 1280 nm, thought to contain a substitutional C (C s ), C i , and an interstitial Si (Si i ) [4,15,19,20]), and the W center (1019 meV, or 1217 nm, thought to consist of three Si i [21][22][23]). All three produce strong photoluminescence (PL) in 28 Si irradiated with 10 MeV electrons, and the G center also has relatively strong absorption transitions.…”

Valley Filtering in Spatial Maps of Coupling between Silicon Donors and Quantum Dots

“…Here, we measure the donor/QD energy spectrum by single-electron transport [46,47] to quantify the strength of the intervalley interference processes in the exchange coupling J(R). We note that the tunability of the exchange interaction opens up interesting possibilities to electrically probe small-scale dopant-based quantum simulators [48][49][50], or to perform electrical spin readout on optically active impurity centers in materials like silicon carbide [51,52], silicon [53,54], and diamond [55,56].…”

G-Centre Formation and Behavior in a Silicon on Insulator Platform by Carbon Ion Implantation and Proton Irradiation

“…The G-centre emission at 1280 nm is in the spectral range that is vital in long-haul fiber-optic networks and is ideally suited to silicon intra-chip and inter-chip lowpower data interconnects. A new method fully compatible with complementary metal oxide semiconductor (CMOS) technology to produce the lasing G-centre has been reported (Beaufils et al 2018;Berhanuddin et al 2012b). The technique combines implantation of carbon, subsequent heat treatment followed by high energy proton implantation on bulk silicon substrates to form C s C i complexes and Si interstitials.…”