Performance of vertical type deep UV light-emitting diodes depending on the Ga-face n-contact hole density.

We have demonstrated a vertical UV-C LED composed of the Ga-face n-contact electrodes using the circular shape holes on mesa. In order to understand the dependence of optical performance on the mesa hole density, we varied the number of holes. As the number of holes on mesa increased, both the light output power and the external quantum efficiency of vertical chips have enhanced while preserving the operation voltage. In spite of reduced active area, the efficiency of current injection could be improved by reducing the current density per hole. The increased mesa hole density of vertical chips induces the enhanced light extraction through the sidewall of holes. [ABSTRACT FROM AUTHOR]