Conventional light-emitting diodes (LEDs) face an efficiency droop at low current due to non-radiative recombination overtaking radiative recombination at low carrier density. To overcome this universal problem, we develop LEDs with high efficiency at ultralow current and voltage, using a novel quantum well design and high-quality interfaces to suppress non-radiative recombination and enhance radiative recombination. The device exhibits close to unity internal quantum efficiency at a low current density of <1 × 10−4 A cm−2, more than three orders of magnitude lower than conventional LEDs. The LED bias voltage is reduced to ~30% below the photon voltage (hν/q). Wireless communication is demonstrated at these low-power conditions, which enables new applications in smart dust and sensor networks1,2,3,4,5,6, low-cost block chain and authentication7,8,9, medical applications10,11 and wherever high efficiency at low power is needed. New phenomena such as high-efficiency electroluminescent cooling becomes possible as the LED unity internal quantum efficiency extends to smaller voltage and current.
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The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.
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The authors thank G. Shahidi for support and helpful discussions, K. Mukherjee for material growth at the beginning of this work and D. Kuchta, A. Paidimarri, C. Cabral Jr, C. Subramanian and D. Friedman for helpful discussions. Management support from M. Khare, D. Gil and the IBM Research Frontiers Institute is acknowledged.
The authors declare no competing interests.
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