Cho et al. Nanoscale Research Letters 2011, 6:578 http://www.nanoscalereslett.com/content/6/1/578 Authors’ contributions CJY carried out overall experiments including nanoimprint lithography works as the first author. KJB carried out the fabrication of mico- and nanoscale complex strcutre using PEC etching process. HP was in charge of replication of Si mold using PDMS molding process. JK carried out the fabrication of the LED devices. HSK was in charge of the analysis of property of the LED devices. HL conducted design and analysis of all experiments as a corresponding author. All authors read and approved the final manuscript. Competing interests The authors declare that they have no competing interests. Received: 13 July 2011 Accepted: 31 October 2011 Published: 31 October 2011 References 1. Schubert E, Kim J: Solid-state light sources getting smart. Science 2005, 308:1274-1278. 2. 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