Recombination balance in green-light-emitting GaN/InGaN/AlGaN quantum wells

Recombination balance parameters for GaN/InGaN/AlGaN single-quantum-well gr een-lightemitting diodes are extracted from optical power and carrier lifet ime measurements. The radiative recombination coefficient B is found to dep end on two-dimensional carrier density N, with a low-carrier-density limit of B-0=1.2x10(-4) cm(2)/s. Sublinearity of the light-current characteristic at temperatures greater than or equal to 300 K is associated with a nonrad iative process whose rate is proportional to similar to N-4.8. The external quantum efficiency of 5.5% at 20 mA results from the internal quantum yiel d of 63% and the photon extraction efficiency of 8.7%. At low temperatures, a nonradiative loss term proportional to similar to N-9 is also identified . (C) 1999 American Institute of Physics. [S0003-6951(99)02505-X].