Study of Carbon Nanotubes as Etching Masks and Related Applications in the Surface Modification of GaAs‐based Light‐Emitting Diodes

each boundary in conventional planar LED devices. Electron beam lithography and holography, combined with inductively coupled plasma-enhanced reactive ion etching (ICP-RIE), have been used to fabricate nanostructures on the surfaces of LED devices based on GaN and GaAs materials. Other approaches utilizing photonic crystals [ 11,12 ] and metal oxide nanoparticles [ 13–16 ] have also been explored to enhance the optical performance of III–V compound devices. These techniques are effective in the fi eld of light extraction, but they cannot be used in the LED fabrication industry due to the high costs and low effi ciencies during mass production. In this research, we report a simple method for nanostructure fabrication using super-aligned multiwalled carbon nanotube (SACNT) thin fi lms as etching masks for top–down etching processes. The morphology of the carbon nanotube (CNT) networks can be transferred to the substrate material at the macro scale, as the SACNT fi lms may be fabricated conveniently over an area of square inches. Nanostructures on the scale of 100 nm were fabricated for the fi rst time under a mask defi ned by SACNT networks. With this method, the nanostructured SACNT network morphology signifi cantly increases the optical output power of GaAs devices in comparison with planar GaAs LED devices. As a macroscopic material system that could be put into mass production at low costs, the super aligned multiwall carbon nanotube networks have proved their excellent performance in electrical, optical, and mechanical properties. [ 17–19 ] Carbon nanotubes have also been proven to be effective in the fabrication of microscopic mask structures. [ 20 ]