Heat transfer mapping in 3–5 μm planar light emitting structures

We report on the heat distribution inside a p+-InAsSb(Zn)/n-InAsSbP/n-InAs planar structure, emitting at 4.3 μm at 300 K. The experimental setup consists of both an infrared scanning microscope and a fiber tip as remote heat sensors (spatial resolution of some μm) operating in a time-resolved (10 μs temporal resolution) manner in the 3–5 μm spectral range. By comparing light and heat maps, we show that current crowding generates local hot regions (somewhat like heat traps) and remarkable temperature gradients (up to 3000 °C/cm) inside the emitting structure.