No silicon-based light emitting diodes exist for shortwave infrared (1.6–3.0 μm) band due to bandgap limitations imposed on luminescence wavelengths. To alleviate this problem, we propose a photonic device in which below-bandgap radiation comes as the result of the thermal emission enhanced by free charge carriers generated by the above-bandgap excitation (light downconversion). With this approach, we demonstrate high-temperature (T>300 K) large-area (20×20 mm2) Si emitter with stable high-power output (∼100 mW/cm2) and prescribed spectrum inside the 1.6–3 μm band for applications such as dynamic scene simulation devices operating at frequencies above 1 kHz.

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Silicon light emitting diode arrays made by industrial planar technology and operating at T>300 K in the double injection mode have been shown to be an efficient emitters of the infrared (IR) radiation in the 3–12 μm spectral band. We show that due to free carrier injection in an optically thin base, which makes its emissivity to increase at the wavelengths of the free carrier absorption, the devices have thermal emission output power of 2–3 mW and local power density up to 1 mW/mm2 at T=473 K. The 0.5-mm-thick 6×6 mm2 emitting pixel of an array demonstrates the power conversion efficiency of 13%, a time response of 300 μs, and an apparent temperature of the IR radiation of 400 K, which make the device practical for use in IR dynamic scene simulation techniques.