<title>Bell-shaped light emitting diodes (BS-LED) with a 45 degree corner reflector, deep side-wall, and microlens</title>

A new type Bell Shaped Light Emitting Diode(BS-LED) with a circular 45 degree(s) corner reflector, deep side-wall and microlens is proposed and fabricated. Because the light of in-plane radiation in the active layer of Surface Emitting LED(SE-LED) can be extracted to emission surface by a circular 45 degree(s) corner reflector, the output power saturation phenomena that occur due to the in-plane superluminescence can be considerably improved. So, the light output power and the linearity of light-current curve can be improved efficiently by the corner reflector. The deeply etched side-wall can dramatically improve the external quantum efficiency of LED by side-wall reflection and photon recycling mechanism. Microlens is formed on light emission surface to improve the beam pattern. The fabricated BS-LED shows the dramatically improved external quantum efficiency up to about 8 times than that of conventional LED. The output power improvement is simulated as device design parameters. The BS-LED is characterized using spectrum, near-field pattern and light-current measurement.