Bandgap dependence of current crowding effect in 3–5 µm InAsSb/InAs planar light emitting devices

Abstract

Electroluminescence power profiles and 2D micropatterns have been obtained from InAsSb/InAs planar LEDs tuned at several wavelengths within the 3–5 µm band. Light confined to a small region around the top opaque contact was observed (cw mode, I > 10 mA, T = 300 K). A computer simulation showed that the reason behind the decrease of the emitting area is the current crowding that ensures non-uniform injection into the active region. The effect becomes more apparent in longer wavelength devices (emitting areas of 3.4 and 4.2 µm emitting devices are related as >10:1), providing direct evidence that the current crowding is affected by the bandgap energy of an active layer.