Towards oriented deposition of 2D materials onto arbitrary substrates in high vacuum

Focused deposition of gold nanospheres onto a substrate, recently performed using ion trap levitation techniques in high vacuum, demonstrates the potential for selectively positioning particles at precise locations [1]. However, the spherical particles encounter significant impact forces upon contact with the substrate, leading to substantial bounce-off and difficulties in controlling both their position and orientation. This unwanted bounce arises from the competition between the kinetic energy of impinging particles and the adhesion at the contact area between the substrate and particles. Reliable adhesion is challenging due to the small contact area of a sphere to a planar substrate. A particle with a flat surface oriented parallel to the substrate would provide superior adhesion. To enlarge contact area, we have engineered nano-platelet fabrication techniques through lithography, and developed methods to suspend them as stable colloids; particles can then be introduced into ion traps using electrospray techniques [2]. By utilizing ion traps, we aim to control the movement of these engineered nano-platelets and facilitate their deposition in specific orientations. In this talk, we will share our progress on this oriented deposition technique and discuss its potential applications.

1. [1] J. E. Coppock and B. E. Kane, arXiv:2408.08860 (2024)
   
   [2] C. J. Hernandez and T. G. Mason, J. Phys. Chem. C, 111, 4477-4480 (2007)