The first and second electrodes are separately disposed on the epitaxial layer structure, and the epitaxial layer structure has a RMS roughness less than 3 nm on {HEAD ~ a surface} wherein {TAIL ~ the second electrode} is formed 
wherein
The first and second electrodes are separately disposed on the epitaxial layer structure , and the epitaxial layer structure has a RMS roughness less than 3 nm on { HEAD ~ a surface } wherein { TAIL ~ the second electrode } is formed
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH