Some new photoluminescence features of W line for neutron-irradiated MCz-Si and FZ-Si

Abstract

Photoluminescence (PL) technique has been applied to study W line (1.018 eV) features for MCz-Si and FZ-Si samples irradiated with neutron dose from Ixl0 15 to 3xl0 16 n/cm 2 • The energy of quenching process for W line estimated from Arrhenius plot was found to be 0.3 eV what is closed to the activation energy for vacancy diffusion. This suggests that annihilation of W emission is due to vacancy -interstitial recombination assuming that W-Iine is a tri-interstitial complex, 1 3 • Similar explanation has been suggested in earlier work from positron signal studies. The average thermal energy of dissociation of the defect state responsible for the emission of W line was found to be E = (52+/-5) meV. So we interpret the emission at 1.018 eV as the recombination of an electron and hole at the defect site when one of the particles is strongly bound to the defect with the energy close to 100 meV. This value coincides with the possible donor-like level (0/+) close to valence band edge at Ev+O.1 eV, theoretically predicted for 1 3 complex.

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

“…The W NP line is known to be an electric dipole transition at a trigonal center having spin-zero initial and final states, and showing only a Si isotope shift in its local vibrational mode replicas [21]. It is currently thought to consist of three Si i [21][22][23], and shifted versions of the W-line have been observed in nat Si implanted with different noble gas ions [34]. The W center is thought to exist near more heavily damaged regions, and its linewidth in nat Si is known to decrease with increasing annealing temperature [22].…”

“…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.…”

Detection of Single W-Centers in Silicon

“…Second, its presence is correlated with the degradation of silicon-based components in environments subject to strong radiations like in particle physics experiments . This intrinsic defect can also be created by silicon implantation, neutron irradiation or following laser annealing, and in isotopically purified 28 Si, which enables to drastically reduce its optical linewidth . Recently, the W-center has seen renewed interest for Si-based classical photonics, where it has been used as an active medium in LEDs , and optical resonators .…”