Photophysics of Intrinsic Single‐Photon Emitters in Silicon Nitride at Low Temperatures

A robust process for fabricating intrinsic single‐photon emitters in silicon nitride is recently established. These emitters show promise for quantum applications due to room‐temperature operation and monolithic integration with technologically mature silicon nitride photonics platforms. Here, the fundamental photophysical properties of these emitters are probed through measurements of optical transition wavelengths, linewidths, and photon antibunching as a function of temperature from 4.2 to 300 K. Important insight into the potential for lifetime‐limited linewidths is provided through measurements of inhomogeneous and temperature‐dependent broadening of the zero‐phonon lines. At 4.2 K, spectral diffusion is found to be the main broadening mechanism, while spectroscopy time series reveal zero‐phonon lines with instrument‐limited linewidths.