Origin of forward leakage current in GaN-based light-emitting devices

The authors fabricated GaN-based light-emitting diodes (LEDs) on two different GaN templates with the same LED structure. One on thin GaN template ( ∼ 2 μ m ) with high dislocation density [low ( 10 9 cm − 2 ) ] grown by metal-organic vapor-phase epitaxy (sample A) and the other on thick GaN template ( ∼ 20 μ m ) with comparatively low dislocation density [high ( 10 8 cm − 2 ) ] by hydride vapor-phase epitaxy (sample B). In order to understand the mechanism of leakage current in LEDs, the correlation between current-voltage characteristics and etch pit density of LEDs was studied.