Capacitance-voltage analysis of GaInN light emitting diodes with a polarization matched nanostructure

Capacitances and carrier concentration profiles of GaInN multi-quantum well (MQW) light-emitting diodes (LEDs) are investigated by using capacitance-voltage (C-V ) measurements to understand the effect of a polarization-matched nanostructure on the internal electric field of LEDs. The nanostructure consisted of Si-doped multilayer quantum barriers replaces typical GaN quantum barriers so as to reduce polarization effect created by a lattice-mismatch between quantum wells and barriers. Owing to the change of internal electric field which is caused by the reduction of polarization mismatch in the GaInN MQW active region; (i) the C-V profile of the polarization-matched LED shows a higher slope on the variance of voltage than that of the conventional LED, (ii) the carrier profile of the polarization-matched LED shows a uniform carrier distribution in the active region (i.e., MQW) than that of the conventional LED. These results give insight for understanding the polarization effect in GaInN MQW LEDs on their optical characteristics.