We have reported high internal quantum efficiency (IQE) (∼60%) of photoluminescence (PL) at 470 nm wavelength from oxygenated amorphous silicon nitride (a-SiN_x:O) films. In this work, we explored the dynamics of high PL IQE from luminescent N-Si-O bonding states in a-SiN_x:O films by using a combination of time resolved PL (TRPL) and temperature dependent PL (TDPL) measurements. The TRPL measurements include time integrated PL, microsecond range PL, and nanosecond range PL measurement modes. The a-SiN_x:O films exhibit ns PL decay dynamics that is independent of pumping fluence (W_PF) and uniform across the PL spectrum, which is different from the PL decay behavior in a-SiN_x films. Particularly, we precisely monitored the temporal evolution of the PL spectra profile to verify that the luminescent N-Si-O bonding states are responsible for the observed blue PL with a radiative recombination rate of ∼10⁸ s⁻¹. Such very fast radiative recombination rate can be compared with that in direct band gap CdSe nanocrystals and can also help us to understand the high PL IQE in a-SiN_x:O films. Moreover, by combining the TD-PL lifetimes with the PL IQE values, the temperature dependence of radiative and nonradiative lifetime can be determined.

Last year, we have reported that the internal quantum efficiency of photoluminescence (PL) from amorphous silicon oxynitride (a-SiN_xO_y) films has been achieved as high as 60%. The present work intensively investigated the mechanisms for tunable PL in the 2.05–2.95 eV range from our a-SiN_x:O films, by using a combination of optical characterizations, X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) measurements. The results of XPS, EPR, and photoluminescence excited measurements indicated that the incorporation of oxygen atoms into silicon nitride (a-SiN_x) networks not only reduced the band tail structure disorder (Urbach tail width E_U) but also created N-Si-O (N_x) defect states in the band gap. We have discovered the distinctive PL characteristics from a-SiN_x:O films with various NH_3/SiH₄ ratios. The PL peak energy (E_PL) is independent of the excitation energy (E_exc) and the PL intensity (I_PL) is regardless of the optical band gap (E_opt) but is proportional to the N_x defects concentration, both of which are completely different from the PL characteristics by band tail states recombination mechanism, in which the E_PL is proportional to E_exc (when E_exc ≤ E_opt) and the I_PL is dependent on the relative position of E_exc and E_opt. Based on the N-Si-O bonding configurations and the distinctive PL characteristics, the radiative recombination mechanism through the N-Si-O defect states has been proposed, by which the performance of stimulated emission may be realized in this kind of a-SiN_x:O films.

We report a rapid synthesis method for producing CsSnCl₃:Mn²⁺ perovskites, derived from SnF₂, and investigate the effects of rapid thermal treatment on their photoluminescence properties. Our study shows that the initial CsSnCl₃:Mn²⁺ samples exhibit a double luminescence peak structure with PL peaks at approximately 450 nm and 640 nm, respectively. These peaks originate from defect-related luminescent centers and the 4T¹→6A¹ transition of Mn²⁺. However, as a result of rapid thermal treatment, the blue emission is significantly reduced and the red emission intensity is increased nearly twofold compared to the pristine sample. Furthermore, the Mn²⁺-doped samples demonstrate excellent thermal stability after the rapid thermal treatment. We suggest that this improvement in photoluminescence results from enhanced excited-state density, energy transfer between defects and the Mn²⁺ state, as well as the reduction of nonradiative recombination centers. Our findings provide valuable insights into the luminescence dynamics of Mn²⁺-doped CsSnCl₃ and open up new possibilities for controlling and optimizing the emission of rare-earth-doped CsSnCl₃.

Luminescent amorphous silicon nitride-containing dense Si nanodots were prepared by using very-high-frequency plasma-enhanced chemical vapor deposition at 250 °C. The influence of thermal annealing on photoluminescence (PL) was studied. Compared with the pristine film, thermal annealing at 1000 °C gave rise to a significant enhancement by more than twofold in terms of PL intensity. The PL featured a nanosecond recombination dynamic. The PL peak position was independent of the excitation wavelength and measured temperatures. By combining the Raman spectra and infrared absorption spectra analyses, the enhanced PL was suggested to be from the increased density of radiative centers related to the Si dangling bonds (K0) and N₄⁺ or N₂⁰ as a result of bonding configuration reconstruction.

The influence of N incorporation on the optical properties of Si-rich a-SiC_x films deposited by very high-frequency plasma-enhanced chemical vapor deposition (VHF PECVD) was investigated. The increase in N content in the films was found to cause a remarkable enhancement in photoluminescence (PL). Relative to the sample without N incorporation, the sample incorporated with 33% N showed a 22-fold improvement in PL. As the N content increased, the PL band gradually blueshifted from the near-infrared to the blue region, and the optical bandgap increased from 2.3 eV to 5.0 eV. The enhancement of PL was suggested mainly from the effective passivation of N to the nonradiative recombination centers in the samples. Given the strong PL and wide bandgap of the N incorporated samples, they were used to further design an anti-counterfeiting label.