Current Noise and Efficiency Droop of Light-Emitting Diodes in Defect-Assisted Carrier Tunneling from an InGaN/GaN Quantum Well
The current dependences of the spectral noise density and quantum efficiency in green and blue light-emitting diodes with InGaN/GaN quantum wells (QWs) are measured. It is shown that the noise level greatly increases at high currents at which there is a quantum efficiency droop. The mechanism by which the current noise is formed is associated with hopping transport via the deep states of color centers in GaN across the n barrier of an InGaN/GaN QW. The source of the noise is the hopping resistance of the space-charge region, which limits the current of thermally activated electrons into the QW. The efficiency droop and the increase in noise level are attributed to a change in the electric-field direction near the QW at high injection levels and to an increase in the tunneling leakage of holes from the QW. It is shown that the experimental frequency-related noise spectra having the shape of a Lorentzian spectrum at the working currents are related to the frequency of hopping between deep centers near the InGaN/GaN QW and to Maxwell relaxation in the space-charge region.
- OSTI ID:
- 22945081
- Journal Information:
- Semiconductors (Woodbury, N.Y., Print), Vol. 53, Issue 1; Other Information: Copyright (c) 2019 Pleiades Publishing, Ltd.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7826
- Country of Publication:
- United States
- Language:
- English
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