Long-Range Carrier Diffusion in (In,Ga)N Quantum Wells and Implications from Fundamentals to Devices

Photoluminescence measurements on high-quality (In, Ga)N quantum wells reveal that carriers diffuse laterally to long distances at room temperature, up to tens of microns. This behavior, which shows a pronounced dependence on the excitation density, contrasts with the common expectation of a short diffusion length. The data is well explained by a diffusion model taking into account the full carrier recombination dynamics, obtained from time-resolved measurements. These observations have important implications for understanding the high efficiency of III-nitride emitters, but also for proper interpretation of photoluminescence experiments and for the design of efficient small-scale devices.