  We report a reversal in negative capacitance and voltage modulated light
emission from AlGaInP based multi-quantum well electroluminescent diodes under
temperature variation. Unlike monotonically increasing CW light emission with
decreasing temperature, modulated electroluminescence and negative capacitance
first increase to a maximum and then decrease while cooling down from room
temperature. Interdependence of such electronic and optical properties is
understood as a competition between defect participation in radiative
recombination and field assisted carrier escape from the quantum well region
during temperature variation. The temperature of maximum light emission must
coincide with the operating temperature of a device for better efficiency.
