Effect of thermal annealing treatments on the optical activation of Tb³⁺ -doped amorphous SiC:H thin films

Effect of Eu Doping on the Physical, Photoluminescence, and Photocatalytic Characteristics of ZnO Thin Films Grown by Sol–Gel Method

“…The change in luminescence can be related to the increase in Urbach energy discussed in section 3.4. The increase in Ubrach energy indicates an increase in the density of defect states, which could lead to an increase in the luminescent centers introduced within the forbidden gap under an appropriate excitation . Process of luminescence, also depends on the host electronic properties such as localized states …”

“…Doping wide bandgap semiconductors (WBS) such as ZnO, AlN, GaN, SiN, SiC with rare earth (RE) ions have received the attention of scientific community due to their application in micro and nanooptoelectronics such as display panels, laser material, data storage, fiber amplifiers, and solid state lasers. [1][2][3][4][5] In the recent past, interest has grown due to nature of the electronic levels present in these rare earth elements. [6] Rare earth ions in the trivalent form (RE 3þ ) are almost insensitive to the atomic environment due to the electronic shield provided by the outermost and completely filled 5s 2 and 5p 6 shells.…”

Influence of rapid thermal annealing temperature on the photoluminescence of Tb ions embedded in silicon nitride films

“…The same emission bands were identified also for samples annealed at other temperatures (not shown here). These transitions and their spectral positions are very similar to the emission lines of Tb 3+ ions embedded in silicon oxide [18], silicon oxynitride [19,20], or silicon carbide films [21] and their overall shape does not change after annealing. Finally, it should be underlined that measured PL spectra did not show any signature of the broad matrix-related PL which has been reported by other authors for undoped SiN x films [13,22].…”

“…Nevertheless, it should be pointed out that the optimal annealing temperature can be different if the annealing conditions change or Tb concentration is different. As shown by Guerra et al [21] the annealing of Tb-doped thin films is a rather complicated issue and depends on many factors.…”

“…According to this definition, 〈τ PL 〉 is simply the average amount of time which Tb 3+ ions spend in their excited 5 D 4 states [25]. For this reason, in the simplest case scenario, if there is a non-radiative recombination from 5 D 4 excited states of Tb 3+ ions (such as non-radiative energy transfer to some defect states, energy transfer between Tb 3+ ions [21,26] or multiphonon relaxation), 〈τ PL 〉 will become shorter. Strictly speaking, this behavior is expected only when a competition between radiative and non-radiative recombination is possible for 5 D 4 excited state.…”