Very thin ITO/metal mesh hybrid films for a high-performance transparent conductive layer in GaN-based light-emitting diodes.

In this paper, we introduce very thin Indium tin oxide (ITO) layers (5, 10, and 15 nm) hybridized with a metal mesh to produce high-performance transparent conductive layers (TCLs) in near-ultraviolet light-emitting diodes (NUV LEDs). Using UV-vis-IR spectrometry, Hall measurement, and atomic force microscopy, we found that 10 nm was the optimal thickness for the very thin ITO layers in terms of outstanding transmittance and sheet resistance values as well as stable contact properties when hybridized with the metal mesh. The proposed layers showed a value of 4.56 Ω/□ for sheet resistance and a value of 89.1% for transmittance. Moreover, the NUV LEDs fabricated with the hybrid TCLs achieved ∼140% enhanced light output power compared to that of 150 nm thick ITO layers. Finally, to verify the practical usage of the TCLs for industrial applications, we packaged the NUV LED chips and obtained improved turn-on voltage (3.48 V) and light output power (∼116%) performance.