Figures

Figure 1

Cross-section view of the p-n diode.

Figure 2

Typical I-V characteristic in a log-log scale. Two regimes of tunneling and space charge limited current are identified at low and high biasing, respectively (see text).

Figure 3

EL spectra performed under 1 MHz pulse biasing with several pulse amplitudes.

Figure 4

dc EL spectra at several temperatures, under low bias to avoid heating of the device.

Figure 5

L-I log-log characteristics. Inset: Relative efficiency characteristics, dL/dI vs I. Full and open symbols represent the light measured by a Si photodetector and the integrated EL spectra like those shown in Figure 3, respectively. Solid curves are linear fits in the low and high current injection regimes.

Figure 6

EL spectra recorded at 7V amplitude pulses of different duration.

Figure 7

Time evolution of the violet EL intensity.

Figure 8

EL spectra recorded at 7V amplitude, 200 ns pulses, at several frequencies (duty cycles).

Figure 9

Violet EL intensity observed after different rest time tOFF.

Figure 10

Level recombination model of the GaN UV-blue LED. RD and Si stand for shallow donors, SA for shallow acceptors, DLD and DLA for deep levels behaving as donors and acceptors, respectively, and YBA for the deep acceptors involved in the yellow luminescence. The UV and visible emissions at the p-side region are explained by a simple 3-level system involving levels 2, 1 and 0.

© 1998 The Materials Research Society