Negative capacitance in light-emitting devices

The negative capacitance behavior in light-emitting diodes and laser diodes has been observed and characterized by using ac admittance-voltage method. Experimental results proved that the strong negative capacitance behavior is always accompanied by remarkable light emission. We confirmed that the negative capacitance is an effect of the junction instead of other behavior or measurement error. We presented a numerical calculation by solving one dimension continuity equation based on a simple diode model. The results show that the negative capacitance behavior in light-emitting diodes has great relation to injected carriers recombination in the active region of luminescence. (C) 2009 Elsevier Ltd. All rights reserved.