Figure 4From: Improvement of photon extraction efficiency of GaN-based LED using micro and nano complex polymer structures Scanning electron microscopy (SEM) image of (a) cross-sectional view of the light emitting diode (LED) that was grown on the patterned sapphire substrate; SEM image of surface of the LED device after the reactive ion etching process in the (b) top view and (c) tilt view.Back to article page