Light emitting device, method for manufacturing light emitting device and lighting system having same

A light emitting device comprising:

• a substrate having an upper surface provided with a pattern part on the upper surface, the pattern part including a plurality of first convex portions and a plurality of first even portions;
• a first semiconductor layer on the upper surface of the substrate;
• a second semiconductor layer on the first semiconductor layer;
• a first conductivity type semiconductor layer on the second semiconductor layer;
• an active layer on the first conductivity type semiconductor layer;
• and
• a second conductivity type semiconductor layer on the active layer,
• wherein the plurality of first even portion are separated from each other,
• wherein the first semiconductor layer includes a plurality of second convex portions and a plurality of second even portions disposed on the pattern part such that each separate one of the second convex portions is on a different one of the first convex portions and each separate one of the second even portions is on a different one of the first even portions,
• wherein the second semiconductor layer includes a plurality of air gaps and a plurality of third even portions, wherein only one air gap of the plurality of air gaps is separately disposed on each one of the second convex portions and a corresponding one of the first convex portions,
• wherein each separate one of the third even portions is on a different one of the second even portions, and a first one of the second even portions of the first semiconductor layer is between a first one of the third even portions of the second semiconductor layer and a first one of the first even portions of the pattern part,
• wherein no air gap is disposed on the second even portions of the first semiconductor layer,
• wherein each of the air gaps has a top portion created by two inclined planes that are inclined with respect to the second even portions of the first semiconductor layer, and at least one of the air gaps includes a curved bottom portion at an opposite end from the top portion of the at least one of the air gaps, and
• the curved bottom portion of the at least one of the air gaps is to directly contact the corresponding second convex portion of the first semiconductor layer, and an entirety of the curved bottom portion is closer to the first conductivity type semiconductor layer than every portion of the substrate and the corresponding first convex portion,
• wherein the second semiconductor layer is to directly contact the first semiconductor layer at the plurality of second even portions and at side portions of the plurality of second convex portions of the first semiconductor layer, and the second semiconductor layer is to directly contact the top portion and the two inclined planes of each of the plurality of air gaps, and
• wherein a distance between adjacent two inclined planes of each respective air gap decreases as a distance from the corresponding convex portion increases.