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

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 (SiO4C8H20) as precursor were studied to determine their chemical composition and geometrical dimensions. The deposited material has a refractive index ~n ¼ 1:85 þ i3:9 � 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 com- pensation. Optical characterisation of the photonic band gap effect is currently under investigation.