title: Argon-plasma-induced InAs/InGaAs/InP quantum dot intermixing.
abstract: We report the first study of argon (Ar)-plasma-enhanced intermixing of InAs/InGaAs/InP self-assembled quantum dots (QDs) in an inductively coupled plasma reactive ion etch system. The Ar-plasma exposure creates point defects, which propagate into the QD structure and enhance the intermixing between the QDs and their barrier layers, hence tuning the energy bandgap of the QDs. By optimizing the plasma exposure time and the annealing temperature, we observe (i) a blueshift of 160 nm and an increase in the photoluminescence (PL) intensity of the QD samples immediately after Ar-plasma exposure for 90 s, and (ii) a further increase in the blueshift of 330 nm, accompanied by 2.5-times increase in the PL intensity and 37 nm narrowing in the PL linewidth after subsequent rapid thermal annealing at 720 °C. The ability to generate a large blueshift without degrading the material quality shows that Ar-plasma exposure is an efficient post-growth technique for tuning the energy bandgap of QD structures.
authors: Photonics Research Centre, School of Electrical and Electronic Engineering, Nanyang Technological University, 639798, Singapore.
authors: Zongyou
authors: Z
authors: Yin
authors: Xiaohong
authors: X
authors: Tang
authors: Chee-Wei
authors: CW
authors: Lee
authors: Jinghua
authors: J
authors: Zhao
authors: Sentosa
authors: S
authors: Deny
authors: Mee-Koy
authors: MK
authors: Chin