Polarisation stabilisation of vertical cavity surface emitting lasers by minimally invasive focused electron beam triggered chemistry

I. Utke; M. G. Jenke; C. Röling; P. H. Thiesen; V. Iakovlev; A. Sirbu; A. Mereuta; A. Caliman; E. Kapon

Nanoscale 3 (2011) 2718-2722

Local electron triggered reactions of functional surface adsorbates were used as a maskless, dry, and minimally invasive nanolithography concept to stabilize the polarisation of individual vertical cavity surface emitting lasers (VCSELs) on a wafer in a post-processing step. Using a 30 keV focused electron beam of a scanning electron microscope and injecting volatile organo-metallic (CH3)2Au(tfa) molecules, polarisation gratings were directly written on VCSELs by dissociating the surface adsorbed molecules. The electron triggered adsorbate dissociation resulted in electrically conductive Au-C nano-composite material, with gold nanocrystals embedded in a carbonaceous matrix. A resistivity of 2500 cm was measured at a typical composition of 30 at.% Au. This material proved successful in suppressing polarisation switching when deposited as line gratings with a width of 200 nm, a thickness of 50 nm, and a pitch of 500 nm and 1m. Refractive index measurements suggest that the optical attenuation by the deposited Au-C material is much lower than by pure Au thus giving a low emission power penalty while keeping the polarisation stable. © 2011 The Royal Society of Chemistry.

DOI: https://doi.org/10.1039/c1nr10047e