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

TL;DR

This study compares the quantum-confined Stark effect in InAs/In(Ga)As quantum dots with doped and non-doped barriers, demonstrating that p-doping significantly enhances modulator performance across a wide temperature range.

Contribution

It introduces the use of p-doped barriers in quantum dots to improve the figure of merit for optical modulators, showing a threefold performance increase over non-doped barriers.

Findings

P-doped barriers improve the figure of merit by over 3 times.

Doped barriers eliminate the ground-state absorption peak.

Performance enhancement is consistent from -73°C to 100°C.

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 $\Delta\alpha$ for a reverse bias voltage swing to the loss at $1 V$ $\alpha(1 V)$, $FoM=\Delta\alpha/\alpha (1 V)$. 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$\times$ increase in FoM modulator performance between temperatures of -73 $\deg$C to 100 $\deg$C when compared with the stack with NID QD barriers.