Achieving Wide Operating Voltage Windows in Non-Carrier Injection Micro-LEDs for Enhancing Luminance Robustness

Since the luminance of Micro-LEDs is highly dependent on the injected current density, inevitable voltage fluctuations will lead to luminance fluctuations and weak luminance robustness. In this work, Micro-LED chips working in non-electrical contact and non-carrier injection (NEC and NCI) mode is proposed, which is totally different from the current-injected mode. The luminance of NEC and NCI Micro-LEDs first increases with the increase of the voltage, and the saturation luminance can be obtained during a relatively large voltage range, which is defined as an operating voltage window. Then the luminance decreases when the voltage is further increased. It is demonstrated that the operating voltage windows can enhance luminance robustness. Finally, the insulating layer that is crucial for the operating voltage windows is optimized. And the working mechanisms related to the existence of operating voltage windows are discussed.