Spectra and Quantum Efficiency of Light-Emitting Diodes Based on GaN Heterostructures with Quantum Wells

✍ Scribed by Yunovich, A. E. ;Kudryashov, V. E. ;Mamakin, S. S. ;Turkin, A. N. ;Kovalev, A. N. ;Manyakhin, F. I.

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 237 KB
• Volume: 176
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/(sici)1521-396x(199911)176:1<125::aid-pssa125>3.0.co;2-1

✦ Synopsis

Spectra and quantum efficiency h e of green LEDs based on heterostructures InGaN/AlGaN/GaN with multiple quantum wells were studied at currents J = 10 ± ±6 to 10 ± ±1 A. Minor differences in h e (of AE10% at J % 10 mA) are caused by sufficiently different distributions of effective charges in the space charge regions and the different role of tunnel component of J at low voltages. The main peak in the spectra at low J (" hw max = 2.35 to 2.36 eV) does not depend on the voltage. At J b 0X2 mA the spectral band is shifted with J (" hw max = 2.36 to 2.52 eV). The origin of the standingº and movingº bands is discussed. The model of 2D structures with band tails describes the spectral form with four fitting parameters rather well. A tunnel radiation band is revealed in the long wavelength range (1.93 to 2.03 eV) in the LEDs with a thin space charge region (w 120 nm). The dependence of h e on J has a maximum which correlates with the fitting parameters and J(V) and N A (w) curves. Possible microscopic and macroscopic inhomogeneities in the structures are discussed.