Abstract
Small signal RF impedance of deep ultraviolet (UV) light emitting diodes (LED) is measured as a function of pump current. Bias dependent differential carrier lifetime is extracted from the measured results by a fitting procedure. An observed strong reduction of carrier lifetime from 9 ns to 0.5 ns in the current range of 0.5 mA to 50 mA is attributed to the band-to-band radiative recombination in the LED active layer. The estimation of the carrier density in the active layer and the recombination parameters in deep UV LED emitting at 325 nm is obtained assuming perfect current injection.