Dielectric Response of Light Emitting Semiconductor Junction Diodes: Frequency and Temperature Domain Study

Abstract

We report a change in the dielectric response of AlGaInP based multi quantum well diodes with the onset of modulated light emission. Observed variation in junction capacitance and modulated light emission, with frequency and temperature, suggests participation of slow defect channels in fast radiative recombination dynamics. Our work establishes prominent connection between electrical and optical properties of light emitting diodes and provides a tool to investigate the interesting condensed matter physics of these structures. Our observations demand a generalized physical framework, beyond conventional models, to understand an active light emitting diode under charge carrier injection. We suggest that the low frequency response can compromise the performance of these diodes under high frequency applications. We also suggest how internal quantum well structure can affect modulated light output efficiency of the device.