Ve. Kudryashov et al., Luminescence and electrical properties of InGaN/AlGaN/GaN light emitting diodes with multiple quantum wells, SEMICONDUCT, 33(4), 1999, pp. 429-434
Luminescence spectra of light-emitting diodes based on InGaN/AlGaN/GaN hete
rostructures with multiple quantum wells are studied for currents in the ra
nge J=0.15 mu A-150 mA. The comparatively high quantum efficiency for low J
(J(max)=0.5-1 mA) is a consequence of a low probability for the nonradiati
ve tunnel current. The current-voltage characteristics J(V) are studied for
J=10(-12)-10(-1) A; they are approximated by the function V = phi(k) + mkT
. [ln(J/J(0)) + (J/J(1))(0.5)] + J . R-s. The portion of V proportional to
(J/J(1))(0.5) and measurements of the dynamic capacitance indicate that i-
layers adjacent to the active layer play an important role. The spectra are
described by a model with a two-dimensional density of states with exponen
tial tails in multiple quantum wells. The rise in T with increasing J is de
termined from the short-wavelength decay of the spectrum of the blue diodes
: T = 360-370 K for J = 80-100 mA. An emission band is observed at 2.7-2.8
eV from green diodes at high J; this band may be explained by phase separat
ion with different amounts of In in the InGaN. (C) 1999 American Institute
of Physics. [S1063-7826(99)01404-0].