Tunable Luminescent A-SiNxOy Films with High Internal Quantum Efficiency and Fast Radiative Recombination Rates

Abstract

In this work, we systematically investigated the Nx bonding defects that induced high photoluminescence internal quantum efficiencies (PL IQEs) and very fast radiative recombination processes in amorphous silicon oxynitride (a-SiNxOy) systems. The luminescent N‒Si‒O bonding-related defect states were checked for the XPS, EPR, and temperature-dependent steady-state PL (TD-SSPL) properties. The PL IQEs were calculated from PL quantum yields through the principle of planar geometry optics, and then confirmed by the TD-SSPL properties. The radiative recombination rates [kr(R)] were determined by combining the PL IQE values and ns-PL lifetimes obtained from time-resolved PL measurements. Both the PL IQE, exceeding 72%, and the fast kr(R) (~108 s−1) are proportional to the concentration of Nx defects, which can be explained by N‒Si‒O bonding states related to the quasi-three-level model, suggesting the possible realization of stimulated light emission in a-SiNxOy systems.

Luminescent Amorphous Silicon Oxynitride Systems: High Quantum Efficiencies in the Visible Range

“…The detailed temperature-dependent PL QY values for various R are listed in Table 2 . One can see that, for various R, the variation tendency of the PL QY values was consistent with the variation tendency of N x defect densities [ 32 ], indicating that luminescent N x defects were responsible for the high PL internal quantum efficiencies in our a-SiN x O y systems. The a-SiN x O y samples with R = 1 had a PL QY value of approximately 14.23% ± 0.15% at the lowest temperature range (~8 K), as shown in Figure 9 f.…”

“…By using Equation (1), for the PL peak range of 2.06–2.95 eV, the a-SiN x O y films were found to have PL QY values ranging from approximately 2% to 10% in the visible range at room temperature, as listed in Table 2 . The PL QY of 10.08% ± 0.95 has been achieved at E PL = 2.6 eV, which is higher than those of reported nc-Si-embedded Si-based thin films [ 17 ], a-SiN x O y films [ 32 ], and a-SiC x O y films [ 36 ].…”

“…For a-SiN x O y with R = 1.5, the PL IQE values at room temperature fitted from TD-SSPL measurements are approximately 84.1%, which are consistent with the calculated PL IQE (ε ~ 83.6%) obtained from the direct measurement of PL QYs, and much higher than those of reported nc-Si-embedded Si-based thin films [ 17 , 18 ], a-SiN x O y films. [ 20 , 21 , 22 , 23 , 32 ], and a-SiC x O y films [ 36 ].…”

“…Based on our previous research [ 31 , 32 , 33 , 34 ], in this paper, we systematically demonstrate the high photoluminescence quantum efficiency of a-SiN x O y systems in detail. First, we measured the PL absolute quantum yields directly using a calibrated integration sphere at room temperature.…”

“…In 2000, Pavesi et al first reported on the nc-Si optical gain and stimulated emission at room temperature, and it is expected to become an efficient luminescent material [ 6 ]. Obtaining more suitable Si-based luminescent materials and improving the related fluorescence quantum efficiency has been one of the most difficult tasks in this field for more than two decades [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 ].…”