Room temperature up-conversion electroluminescence from a mid-infrared In(AsN) tunnelling diode

Light emitting diodes (LEDs) for the mid-infrared (MIR) spectral range require material systems with tailored optical absorption and emission at wavelengths  > 2 μm. Here, we report on MIR LEDs based on In(AsN)/(InAl)As resonant tunnelling diodes (RTDs). The N-atoms lead to the formation of localized deep levels in the In(AsN) quantum well (QW) layer of the RTD. This has two main effects on the electroluminescence (EL) emission. By electrical injection of carriers into the N-related levels, EL emission is achieved at wavelengths significantly larger than for the QW emission ( ~ 3 m), extending the output of the diode to  ~ 5 m. Furthermore, for applied voltages well below the flat band condition of the diode, EL emission is observed at energies much larger than those supplied by the applied voltage and/or thermal energy, with an energy gain E > 0.2 eV at room temperature. We attribute this up-conversion luminescence (UCL) to an Auger-like recombination process.