Positive impact of surface defects on Maxwell's displacement current-driven nano-LEDs: The application of TENG technology

Abstract

As the core component of a nanopixel light-emitting display, the GaN-based nanoscale light-emitting diode (nLED) faces the problem of low electroluminescence efficiency resulting from the introduction of surface defects when its lateral size is reduced to the nanometer scale. Thus, reducing the surface defect density is an important direction in nLED-related research. This study, with the triboelectric nanogenerator-driven LED as its inspiration, reveals that surface defects have a positive impact on the performance of nLEDs driven by Maxwell’s displacement current, and we call the related driving mode the noncarrier injection mode. Through finite element simulations, we studied the dynamic variations of the carrier concentration, the energy band, and the light emission rate to analyze the impact of the behavior of surface defect excitation on device performance. We found that surface defects can act as electron pumps under the combined effect of the reverse electric field and the built-in electric field and can generate carriers through surface defect excitation to increase the intensity of noncarrier injection luminescence, which is completely different from the traditional understanding of surface defects. In addition, we propose a tapered structure to further increase the light emission rate by regulating the behaviors of radiation recombination and surface defect excitation. The results of this work open a new perspective on the impacts of surface defects on nLEDs and provide significant information for additional applications of Maxwell's displacement current.