Effect of ITO Interface Modulation Layer on The Performances of LEDs with Ga-doped ZnO Electrode

Indium-Tin-Oxide(40 nm)/Ga-doped ZnO(140 nm)(ITO/GZO) and GZO(180 nm) films were deposited onto both glass substrates and p-GaN epitaxial layers by magnetron sputtering as transparent current spreading layer of GaN-based LEDs.After thermal annealing in air ambient conditions,the ITO/GZO films exhibite high transparency(~80%) in visible light and low resistivity(1.15×10-3 Ω·cm).The roughness of the ITO/GZO films is bigger than that of the GZO films which enhances the extraction of photons.The ITO interface modulation layer can reduce the contact barrier of GZO/p-GaN and improve the photoeletric performance of LEDs.GaN-based light-emitting diodes(LEDs) were also fabricated.With 20 mA injection current,it is found that the forward voltage are 6.8 V and 9.5 V,while the luminous intensity are 297 mcd and 245 mcd,respectively for the LEDs with ITO/GZO electrode and GZO electrode.Compared the LEDs with GZO electrodes,the luminous intensity of LEDs with ITO/GZO electrode increased by 20% at 20 mA forward current and increased by 50% at 35 mA forward current.