Abstract

InGaN-based light emitters are promising technology for next-generation display and AR/VR applications, offering high resolution, brightness, and stability. To meet industrial requirements, further performance enhancements are essential. As such, this thesis explores two key approaches: first, minimizing sidewall defects caused by harsh dry etching processes, and second, enhancing light extraction efficiency (LEE) through the use of transparent p-electrodes.

A selective passivation technique for p-GaN using hydrogen plasma treatment is demonstrated to enhance the performance of InGaN single quantum well (SQW) red light-emitting diodes (LEDs). Insulating regions are created on the p-GaN surface, suppressing current injection beneath the p-pad and along the mesa edges, thereby allowing improved light output and reduced non-radiative recombination. Additionally, the temperature dependence of InGaN SQW red LEDs is explored in comparison to AlGaInP counterparts, revealing superior thermal stability and minimal wavelength shifts in InGaN LEDs.

Further analysis focuses on improvement in LEE for micro-LEDs. Transparent indium tin oxide (ITO) p-electrodes are introduced to replace traditional opaque metal electrodes in InGaN green and red micro-LEDs, aiming to enhance light output. ITO p-electrodes exhibit high transmittance and low resistivity, whereas metal electrodes have low transmittance and significant absorption. ITO p-electrode thickness is optimized. An enhancement in LEE for InGaN red and green micro-LEDs of various sizes operating at low current densities is demonstrated. The performance of micro-LEDs with ITO p-electrodes is compared to those with conventional metal p-electrodes, showing improved light output and efficiency. Light ray tracing simulations further confirm the superior light escape capability of ITO p-electrodes, highlighting their role in enhancing light extraction. These findings provide valuable insights for developing high-performance micro-LEDs in high-definition display and artificial reality (AR) / virtual reality (VR) applications.