Focused electron beam induced deposition of a periodic transparent nano-optic pattern

Abstract

In this paper we describe the fabrication of a two-dimensional photonic band gap structure by focused electron beam induced deposition. Structure geometry is computed in order to create a light-trapping effect at 632 nm wavelength. Deposits produced using tetraethyl orthosilicate (SiO 4C 8H 20) as precursor were studied to determine their chemical composition and geometrical dimensions. The deposited material has a refractive index n ̃ =1.85+ i 3.9×10 −4 at 632 nm. Transmission electron microscopy revealed deposits obtained at low currents (100 pA) are amorphous. The structure was deposited on a quartz prism, coated with a transparent conducting antimony-doped tin oxide layer to minimize electron beam drifts and distortions. Multiple beam re-alignments during the deposition assured drift compensation. Optical characterisation of the photonic band gap effect is currently under investigation.