Enhancement of green emission from InGaN/GaN multiple quantum wells via coupling to surface plasmons in a two-dimensional silver array

A novel approach to enhancing the emission efficiency of InGaN/GaN multiple quantum wells via coupling to surface plasmons (SPs) in a periodic two-dimensional silver array is demonstrated. A higher internal quantum efficiency and a higher light extraction efficiency are simultaneously achieved by engraving an array of nanoholes into the p-GaN cladding layer, followed by partial filling with silver. By top excitation and collection from the top of the Ag-incorporated light emitting diodes (LEDs), a 2.8-fold enhancement in peak photoluminescence intensity is demonstrated. The proposed nanoengraving technique offers a practical approach to overcoming the limitation of the exponentially decayed SP field without sacrificing the thickness of the p-GaN layer and to controlling the effective coupling energy. The approach is feasible for high-power lighting applications.