Enhanced Wall-Plug Efficiency in AlGaN-Based Deep-Ultraviolet LED via a Novel Honeycomb Hole-Shaped Structure

The novel honeycomb hole-shaped electrode (HHSE) structure was proposed for 280-nm AlGaN-based flip-chip deep-ultraviolet light emitting diode (DUV-LED), which was demonstrated to be beneficial to the current spreading, optical emission, and heat dispersion. By means of the finite element method, we investigated the current density distribution at an injection current density of 67.5 A/cm2 and found that the effective current spreading area was approximately improved by 35.3% for the light emitting diode (LED) with a novel electrode compared with the LED with the conventional finger-shape electrode. As a result, the wall-plug efficiency (WPE) of the LED with a novel electrode was increased by 28% at an injection current of 280 mA. Meanwhile, the symmetrical distribution of optical emission and temperature was realized. This paper paves the way to solve the current crowding effect due to the poor conductivity of the n-AlGaN layers with high Al fraction and significantly develop high efficiency in the AlGaN-based DUV-LED.