Electron beam induced deposition and etching (EBID and EBIE) are direct-write nanofabrication techniques in which an electron beam is used to dissociate surface-adsorbed precursor molecules to achieve nanostructure etching or deposition inside an environmental scanning electron microscope. Here, we will discuss recent experimental work on directed deposition and etching of fluorescent diamond nanoparticles and the two-dimensional semiconductor hexagonal boron nitride. First, we use an ammonia plasma to functionalize the surfaces of EBID-fabricated nanoscale carbon seeds (Fig. 1a) with amine groups. Covalent bonding of nanostructures such as nanodiamonds and gold colloids to the amine-functionalized seeds is then achieved by carbodiimide coupling chemistry. To ascertain the nanodiamond attachment yield and selectivity of the technique, we employ confocal microscopy to obtain photoluminescence maps and spectra of the fabricated arrays. The bright fluorescent spots in Fig. 1b correspond to the emission (Fig. 1c) from nitrogen vacancy defects in the nanodiamonds, demonstrating successful attachment. Our attachment process is applicable to a wide variety of substrates and offers unprecedented stability, which we demonstrate by subjecting the fabricated nanodiamond arrays to up to 12 hours sonication. We demonstrate the utility of our process by assembling fluorescent nanodiamonds into large area arrays that can be utilized as magnetic field sensors. We also demonstrate high resolution EBIE of the two dimensional semiconductor hexagonal boron nitride in a background atmosphere of water vapour. The hBN undergoes denitrogenation under electron beam induced etching in H2O, forming volatile NO and NO2 and resulting in highly localized, clean etching of the hBN. Raman analysis demonstrates that the surrounding hBN material is not damaged by the etch process, enabling damage-free fabrication of well-defined hBN nanoribbons, holes and other geometries.

Directed deposition and etching of functional nanostructures using electron beam and plasma irradiation

253rd National Meeting (2017)

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