Quantum Emitters with Narrow Band and High Debye-Waller Factor in Aluminum Nitride Written by Femtosecond Laser.

Solid-state quantum emitters (QEs) are central components for photonic-based quantum information processing. Recently, bright QEs in III-nitride semiconductors, such as aluminum nitride (AlN), have attracted increasing interest because of the mature commercial application of the nitrides. However, the reported QEs in AlN suffer from broad phonon side bands (PSBs) and low Debye-Waller factors. Meanwhile, there is also a need for more reliable fabrication methods of AlN QEs for integrated quantum photonics. Here, we demonstrate that laser-induced QEs in AlN exhibit robust emission with a strong zero phonon line, narrow line width, and weak PSB. The creation yield of a single QE could be more than 50%. More importantly, they have a high Debye-Waller factor (>65%) at room temperature, which is the highest result among reported AlN QEs. Our results illustrate the potential of laser writing to create high-quality QEs for quantum technologies and provide further insight into laser writing defects in relevant materials.

Optical Visualization of Photoexcitation Diffusion in All-Inorganic Perovskite at High Temperature.

All-inorganic halide perovskites are promising candidates for optoelectronic and photovoltaic devices because of their good thermal stability and remarkable optoelectronic properties. Among those properties, carrier transport properties are critical as they inherently dominate the device performance. The transport properties of perovskites have been widely studied at room and lower temperatures, but their high-temperature (i.e., tens of degrees above room temperature) characteristics are not fully understood. Here, the photoexcitation diffusion is optically visualized by transient photoluminescence microscopy (TPLM), through which the temperature-dependent transport characteristics from room temperature to 80 °C are studied in all-inorganic CsPbBr3 single-crystalline microplates. We reveal the decreasing trend of diffusion coefficient and the almost unchanged trend of diffusion length when heating the sample to high temperature. The phonon scattering in combination with the variation of effective mass is proposed for the explanation of the temperature-dependent diffusion behavior.