sectional views of the led die taken along a a u2032 line in fig1 a in fig1 b the structure of the led die 100 from bottom to top is a transparent substrate 120 an n type semiconductor layer 130 a light emitting layer 140 a p type semiconductor layer 150 and an electrode 160 in which the recess structures 110 are positioned on the sidewalls of the transparent substrate 120 according to one embodiment of the present disclosure the recess structures 110 are positioned on the sidewalls of the transparent substrate 120 and the n type semiconductor layer 130 as shown in fig1 c according to another embodiment of the present disclosure the recess structures 110 are positioned on the sidewalls of the n type semiconductor layer 130 according to one embodiment of the present disclosure the material of the transparent substrate 120 is selected from the group of sapphire silicon silicon carbide sic diamond quartz and the combinations thereof otherwise in fig1 b the sidewalls of the transparent substrate 120 and the n type semiconductor layer 130 further comprises a chamfer structure u03c6 according to one embodiment of the present disclosure the chamfer structure u03c6 has angle in a range of 30 u00b0.