<title>Frequency limits of high-efficiency non-resonant cavity light-emitting diodes</title>

Abstract

In this paper, we present measurements of the switch-on times and of the switch-off times of non-resonant cavity light-emitting diodes, compared to those of conventional reference diodes. From this comparison, we infer that the high quantum efficiency of NRC-LED's is not achieved by photon recycling, but purely by efficient extraction of generated photons. This is further corroborated by the good matching that is achieved between the measured switch-on times and theoretical predictions of the switch-on times. The latter are calculated with a model that includes only the electrical charging of the active layer and assumes that photon recycling does not occur. It is furthermore shown that the switch-on can be made faster by switching the diode between a non-zero low-state and the required high state. Doing so, an open eye diagram is achieved at 622 Mbit/s for a NRC-LED having an external quantum efficiency of 17%.