Gas-phase formation of 2D GaSe quantum dot ensembles in a nonequilibrium laser ablation process

Further geometrical confinement of the Two-dimensional (2D) materials in lateral dimensions toward zero-dimensional (0D) structures can form 2D nanoparticles and quantum dots with new properties. Here, we report the formation of quantum dots-like gallium selenide (GaSe) nanoparticles ensembles in a nonequilibrium gas-phase synthesis method. We show that by condensing the laser-generated plume in an argon background gas, metastable nanoparticles can form in the gas phase via the plume condensation process. The deposition of nanoparticles onto the substrates results in the formation of nanoparticle ensembles, which are then post-processed to crystallize or sinter the nanoparticles. The effects of background gas pressures and crystallization/sintering temperatures on the properties of the generated nanoparticles are systematically studied. This method offers a clean and fast route toward the formation of various 2D nanoparticles for potential optoelectronic and photonic applications.