Field-Effect Passivation of GaN-Based Blue Micro-Light-Emitting Diodes

We demonstrate field-effect passivation (FEP) of GaN-based blue <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula> LEDs by incorporating an additional metal-oxide-semiconductor gate structure on the sidewalls. This approach allows for active control of surface band bending at the sidewalls, thereby modulating carrier trapping and de-trapping. We observe that applying a negative gate voltage <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$(V_{G})$ </tex-math></inline-formula> facilitates electron de-trapping, leading to a reduction in surface recombination and a corresponding decrease in current, as evidenced by an enhanced external quantum efficiency (EQE). Conversely, applying a positive <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V_{G}$ </tex-math></inline-formula> results in the opposite effect.