Broadband antireflection silicon carbide surface by self-assembled nanopatterned reactive-ion etching

An approach of fabricating pseudoperiodic antireflective subwavelength structures on silicon carbide by using self-assembled Au nanopatterns as etching mask is demonstrated. The nanopatterning process is more time-efficiency than the e-beam lithography or nanoimprint lithography process. The influences of the reactive-ion etching conditions and deposited Au film thickness to the subwavelength structure profile and its corresponding surface reflectance have been systematically investigated. Under the optimal experimental conditions, the average reflectance of the silicon carbide in the range of 390-784 nm is dramatically suppressed from 21.0 % to 1.9 % after introducing the pseudoperiodic nanostructures. A luminescence enhancement of 226 % was achieved at an emission angle of 20 degrees on the fluorescent silicon carbide. Meanwhile, the angle-resolved photoluminescence study presents a considerable omnidirectional luminescence enhancement. (C) 2012 Optical Society of America