Reliable deposition of gold nanoparticle projectiles launched from an ion trap

We have succeeded in depositing single gold nanoparticles initially levitated in an ion trap onto a substrate with sticking probabilities around 90%. Our research uses a two-part approach to study the material properties of nanoparticles: first, optical and thermodynamic measurements are made while the particle is levitated in an electric field trap in high vacuum; next, as a complement to the levitated measurements, we deposit the particle on a substrate that can be removed for study via microscopy. The nanoparticles (of diameter 250 nm) are given electric charge and delivered to the trap from a liquid suspension via electrospray ionization, and a single particle is studied using laser scattering. Next, the particle is expelled from the trap with velocity of order 10-20 m/s. A laser liquefies the particle during travel to promote sticking at the substrate. The location of the particle on the substrate is determined using camera imaging. In the talk, we will present preliminary data on the focusing of the particle’s deposition location using an electrostatic lens.