Holographic Fabrication of Photonic Crystals by Double-Beam Exposure Method for Improving the Extraction Efficiency of LED

Light Emitting Diode (LED) has been developing rapidly in recent years because of its various characteristics, such as small size, long life, high brightness, low calorific power and so on. But the poor efficiency of light extraction is the major factor which constrains the development of LED. The two-dimensional (2D) photonic crystals (PhCs) are very suitable for improving the efficiency of light extraction. The PhCs whose size is centimeter level can be fabricated by holographic lithography. It is low cost and easier for the industrialization of production. To research the condition of making 2D PhCs for improving the efficiency of light extraction, we use 532nm laser as the light source and SU-8 negative photoresist as the mask. The 2D PhCs whose duty cycle is 1:1 are created by double-beam double exposure method. It is verified that the PhCs can be used to improve the efficiency of light extraction.