Photoinduced absorption study of carrier dynamics in Ru-doped Bi12SiO20 crystals after nanosecond laser pulse excitation

Abstract

The charge carrier dynamics in the sillenite type crystal Bi 12 SiO 20 ͑BSO͒ doped with ruthenium is studied by monitoring the optical density changes after nanosecond laser pulse excitation using a frequency-doubled Nd:yttrium aluminum garnet laser. Ruthenium doping leads to a relatively high density of trap levels that significantly increase the relaxation time of excited charge carriers in comparison with a nondoped BSO. Relaxation dynamics with two different decay time constants is observed in BSO:Ru in the studied submicron to 100 s time range and their dependences on pump intensity and on temperature are investigated. From the observed temperature dependence of the slower and faster of the two decay components, thermal activation energies of E a,s = 0.80Ϯ 0.03 eV and E a,f = 0.68Ϯ 0.03 eV were determined, respectively. The results indicate that in BSO:Ru at least two different traps centers are involved in the long-lived photoinduced carrier dynamics.

Excitations in doped quantum dot driven by discontinuously and randomly reversing electric field: Influence of impurity

“…The dopant strength, dopant location, and the region over which the influence of the dopant is disseminated modulate the excitation rate with subtlety. Recently, there were some excellent experiments on carrier dynamics of doped quantum dot structures [46][47][48]. We hope that our findings could be practically exploited in designing impurity doped quantum dot devices for engineering applications.…”

Effect of impurity strength and impurity domain on excitation of doped quantum dot induced by discontinuously reversing pulsed field

“…[42][43][44] We hope that our findings could be practically exploited in designing impurity doped QD devices for engineering applications. The dopant strength and the region over which the influence of the dopant is disseminated modulate the excitation rate with subtlety.…”

Quasi-nonvolatile storage in Ru-doped Bi_12SiO_20 crystals by two-wavelength holography

“…Further electron paramagnetic resonance direct detection proved that Ru doping results in (Bi 3+ Si + h) center already in the as-grown crystal and Ru introduces electron accepting levels close to the valence band (VB) [17]. Recently, photoinduced absorption study reveal an evidence of Ru-related high density of trap levels (positioned more shallow than the deep levels typical for sillenites), acting as acceptor centers for photoexcited electrons [18]. Based on above results and detected broad absorption peak after green light pre-excitation [14], we suppose that Ru addition introduce trap centers, which are located more shallow than the main photorefractive level at 2.2 eV.…”