Measurement of the quantum-confined Stark effect in InAs/In(Ga)As quantum dots with p-doped quantum dot barriers

Abstract

The quantum-confined Stark effect in InAs / In ( Ga ) As quantum dots ( QDs ) using non-intentionally doped and p-doped QD barriers was investigated to compare their performance for use in optical modulators. The measurements indicate that the doped QD barriers lead to a better figure of merit ( FoM ), defined as the ratio of the change in absorption Δ α for a reverse bias voltage swing to the loss at 1 V α (1 V ), FoM =Δ α / α (1 V ). The improved performance is due to the absence of the ground-state absorption peak and an additional component to the Stark shift. Measurements indicate that p-doping the QD barriers can lead to more than a 3 x increase in FoM modulator performance between temperatures of −73 °C to 100 °C when compared with the stack with NID QD barriers.