Spectra of superbright blue and green InGaN/AlGaN/GaN light-emitting diodes

• Published in: Journal of the European Ceramic Society 1997, Vol.17 (15), p.2033-2037
• Main Authors: Kudryashov, V.E., Turkin, A.N., Yunovich, A.E., Zolina, K.G., Nakamura, S.
• Format: Article
• Language: English
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/S0955-2219(97)00054-X

Electroluminescence spectra of blue and green light-emitting diodes (LEDs) based on In xGa 1 − xN/Al yGa 1 − yN/GaN heterostructures with a thin quantum well active layers were studied at currents J = 0.01–20 m A. Spectral maxima of blue LEDs are ω max = 2.58–2.75 eV, of green are ω max = 2.3–2.45 eV, depending on the In content in the active layer. The low and high energy tails of the spectra are exponential with the parameters E 0 = 42–50 meV and E 1 ≈ 1–1.3 kT, respectively. The spectra can be described taking into account quantum-size effects, impurities and fluctuations in active layers. An interference structure in spectra was detected. Light intensity depended on J linearly in the interval 1–20 m A. Efficiency of blue LEDs dropped at J < 0.7 mA as I~ J 4–5 (300 K). The green LEDs had no such dependence. Tunnel radiation spectra with maxima moving with the voltage were detected at low J.