Thin-film metallization of CuInGaSe₂ nanoparticles by supersonic kinetic spraying

High-speed spraying quickly deposits dry, solid particles at atmospheric pressure, without the use of binders, across large coating areas. We experimentally deposited Al₂O₃ and copper-indium-gallium-selenium (CIGS) nanoparticles on Al₂O₃ and molybdenum substrates and numerically replicated the results to elucidate the details of the deposition mechanisms. Thin films formed from layers of sprayed-particle impacts. Both single- and multiple-particle impacts are simulated and increases in pressure, temperature and von Mises stress are reported. Both experimentally and numerically, micron-sized particles are pulverized into flattened layers of nano-sized particle fragments. Characterizing the impact physics (particle collapse speed, energy exchange, and substrate damage) helps identify the optimum operating envelope for particle speeds less than 200 m/s that maximizes thin-film growth rates and minimizes substrate damage.