{HEAD ~ The method} 6, wherein the first refractive index adjustment layer is formed on the n type nitride semiconductor layer and has {TAIL ~ a refractive index} less than that of the n type nitride semiconductor layer, and 
{ HEAD ~ The method } 6 , wherein the first refractive index adjustment layer is formed on the n type nitride semiconductor layer and has { TAIL ~ a refractive index } less than that of the n type nitride semiconductor layer , and
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH