Light Emitting Diodes (LEDs) made of nitride materials are universally used for energy-efficient lighting. However, such LEDs suffer from drastic drops in efficiency at high current densities and high emission wavelengths (green to red), whose causes are still debated due to their complexity. Understanding them requires to access carrier behavior inside the active region of the LED itself, taking into account microscopic structuration and heterogeneities. Most approaches in the literature focus on spatially averaged measurements, missing out the core of the problem. This project proposes to develop a novel approach to directly image carrier behavior (injection, recombination et escape) in the active region of an in operando LED. The aim is to perform a pump-probe electrical and optical excitation on a cleaved device observed in cross-section in a low energy electron microscope. This approach includes several challenging steps, among them the cleavage of an operating device for an observation in cross-section and the development of a mixed electrical and optical excitation of the LED under the microscope. Numerical modelling will be developed to support experimental findings.