Fluorolo 3 system

The chemical compositions and atomic scale defect states were confirmed by the XPS (Thermo ESCALAB 250, ThermoFisher Scientific, Waltham, MA, USA) and the EPR (Bruker EMXplus, X-band, Bruker, Billerica, MA, USA) measurements. The TD-SSPL and PL excited (PLE) properties were measured by a Fluorolo-3 system (HORIBA Jobin Yvon, Paris, France) in a computer-controlled Delta 9023 oven (State College, PA, USA) under various temperatures, using a 75W Xe lamp (λ_exc = 250‒800 nm) and a He‒Cd laser (λ_exc = 325 nm) as light sources. The optical band gaps (E_opt) were obtained from transmittance measurements (Shimadzu UV-3600, Shimadzu Corp., Hadano, Kanagawa, Japan). The refractive indexes (n) were measured using a spectroscopic ellipsometer (Jobin Yvon UVISEL, HORIBA Jobin Yvon, Paris, France). Both the E_opt and n of a-SiN_xO_y samples are listed in Table 1. A FLS980 (Edinburgh Instrument Ltd., Edinburgh, UK) equipped with an EPL375 pulse diode laser (λ_exc = 375 nm, pulse width ~53 ps, repetition rate ~20 MHz), and a TCSPC (resolution time ~100 ps), were used to record the time-resolved PL.

The films were structurally characterized with a Thermo ESCALAB 250 X-ray photoelectron spectrometer (XPS) with an excitation source of monochromatic Al K-alpha rays (1486.6 eV). The Tauc’s optical gap (E_opt) under different R conditions was obtained from transmittance measurements at room temperature, which were performed using a Shimadzu UV-3600 spectrophotometer. The steady-state TD-PL properties were measured with a Fluorolo-3 system (Jobin Yvon) and a HP4284 LCR meter in a computer-controlled Delta 9023 oven, using a 75 W Xe lamp (excitation wavelength λ_exc = 250–800 nm) and a He–Cd laser (λ_exc = 325 nm, output power 30 mW) as light sources. As comparative references, controlled a-SiN_x films with different flow ratios R were also prepared and the corresponding characteristics were measured under the same conditions. Before we performed all the measurements, we carefully checked and corrected the intensity of the light source, the response of the detector, the influencing factors of sample holders, and the sample’s morphology. All the recorded PL spectra were background-corrected.