Light extraction behavior of GaN-based light-emitting diodes with different substrate conditions; nano-size and micro-sized sapphire substrates??

摘要

We fabricated InxGa1−xN multiple quantum well (MQW) light-emitting diodes (LEDs) on patterned sapphire substrates (PSSs); the nano-sized PSS (NPSS) and the micro-sized PSS (MPSS), and investigated to enhance the light extraction efficiency (LEE) of LEDs. Furthermore, the micro-Raman and ER spectroscopy were used to compare the strain and piezoelectric fields in the InxGa1−xN MQWs grown on the different substrate conditions. The light output power (at 20mA) of the MPSS and NPSS are 11.4 mW and 11.6 mW, which are enhanced by 39% and 41% compared with that of the conventional LED, respectively.