ITO界面调制层对GZO电极LED器件性能的影响

采用磁控溅射制备GZO和具有ITO界面调控层的GZO(ITO/GZO)透明导电薄膜作为大功率LED的电流扩散层,对比研究界面调控层对LED器件性能的影响。研究结果表明,ITO/GZO薄膜的透过率在可见光区达80%以上,退火后的ITO/GZO薄膜有较低的电阻率(1.15×10^-3 Ω·cm)。ITO调控层的介入能够调制GZO表面粗糙度,有利于改善LED外量子效率,降低GZO/p-GaN界面的接触势垒,提高LED器件的光电性 能。通过ITO界面调控后,LED器件20 mA驱动电流下的工作电压从9.5 V降低为6.8 V,发光强度从245 mcd 升到297 mcd,提高了20%;驱动电流为35 mA时,其发光强度从340.5 mcd 升到511 mcd,提高了50%。

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.