Injection characteristics of polar and nonpolar multiple-QW structures and active region ballistic overshoot

Electron ballistic overshoot of the active region is shown to dominate the leakage current in light‐emitting III‐nitride multi‐QW diode structures. At high injection levels typical for laser diodes, the overshoot‐assisted leakage is comparable in polar and nonpolar structures whilst in the low injection LED regime nonpolar structures reveal much smaller leakage; this complies with available observations of LED efficiency droop. We show that drift‐diffusion approximation for electron transport noticeably underestimates the leakage, especially in nonpolar structures. Ballistic spill‐over also increases the electron concentration in p ‐side waveguide layers and enhances the nonradiative recombination loss. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)