Effect of Sputtered AlN Location on the Growth Mechanism of GaN

Patterned sapphire substrates (PSSs) have been used to enhance the performance of GaN-based light-emitting diodes (LEDs). This performance can be further improved by using an ex situ sputtered AlN nucleation layer. This improvement has been attributed to the reduction of the GaN formation on the sidewall of the cone shape pattern. In this study, four kinds of PSS samples were fabricated to investigate the effect of sputtered AlN location on the growth mechanism of GaN in detail.