Effects of ITO Contact Sizes on Performance of Blue Light MicroLEDs

Yu Hsuan Hsu, Yu Yun Lo, Yi Hsin Lin, Hsiao Wen Zan, Ray Hua Horng*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


In this study, the effect of ITO contact ratio for blue light micro-light-emitting diode (µLED) with dimensions 40 μm × 40 μm was assessed. The contact ratio from 0.2 to 0.8 was designed for the ratio of electrode area to light-emitting area. As the contact ratio increased from 0.2 to 0.8, the turn-on voltage of µLED decreased. It could be due to the short lateral diffusion length in multiple quantum wells (MQW) and lower parallel resistance for the µLED with a large contact ratio. The leakage currents of single µLED were below 5.1 × 10–9 A, no matter the contact ratio. It means that the contact ratio does not affect the leakage current as measured on single chip. Moreover, µLED array with a 0.8 contact ratio presented the highest output power than other samples (5.25 mW as the current density of 1875 A/cm2). It could attribute to the MQWs usage, the metal contact reflective behavior and less current crowding, which generated more carriers and extracted more lighting from the µLED. The simulation data using SpeCLED software agreed well with these experiments, and µLED with a 0.8 contact ratio showed the best optoelectronic properties.

Original languageEnglish
Article number113
JournalNanoscale Research Letters
Issue number1
StatePublished - 2022


  • Blue light
  • Contact ratio
  • Current crowding
  • Micro-LED


Dive into the research topics of 'Effects of ITO Contact Sizes on Performance of Blue Light MicroLEDs'. Together they form a unique fingerprint.

Cite this