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 Δ𝛼 for a reverse bias voltage swing to the loss at 1 𝑉 𝛼(1 𝑉), 𝐹𝑜𝑀 = Δ𝛼/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 3𝑥 increase in 𝐹𝑜𝑀 modulator performance between temperatures of −73 • 𝐶 to 100 • 𝐶 when compared with the stack with 𝑁 𝐼 𝐷 𝑄𝐷 barriers.