A new fabrication method to improve the optical extraction efficiency of light-emitting devices is presented. The morphology of a self-assembled block copolymer was transferred to the surface of a compound semiconductor to achieve a subwavelength columnar structure. The optical extraction efficiency of the substrates with subwavelength columnar structures of 350 nm pillar height, 130 nm diameter, and 180 nm pitch, improved 2.2 times compared to unprocessed substrates. This method does not require expensive exposure lithography tools and is therefore suitable for conventional semiconductor processes.
© 2005 Optical Society of America
(220.3740) Optical design and fabrication : Lithography
(230.1950) Optical devices : Diffraction gratings
(230.3670) Optical devices : Light-emitting diodes
(230.4000) Optical devices : Microstructure fabrication
(240.6700) Optics at surfaces : Surfaces
Koji Asakawa and Akira Fujimoto, "Fabrication of subwavelength structure for improvement in light-extraction efficiency of light-emitting devices using a self-assembled pattern of block copolymer," Appl. Opt. 44, 7475-7482 (2005)