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Optical Engineering • Open Access

InAs/GaAs quantum-dot intermixing: comparison of various dielectric encapsulants
Author(s): Hala H. Alhashim; Mohammed Zahed Mustafa Khan; Mohammed A. Majid; Tien K. Ng; Boon S. Ooi

Paper Abstract

We report on the impurity-free vacancy-disordering effect in InAs/GaAs quantum-dot (QD) laser structure based on seven dielectric capping layers. Compared to the typical SiO2 and Si3N4 films, HfO2 and SrTiO3 dielectric layers showed superior enhancement and suppression of intermixing up to 725°C, respectively. A QD peak ground-state differential blue shift of >175  nm (>148  meV) is obtained for HfO2 capped sample. Likewise, investigation of TiO2, Al2O3, and ZnO capping films showed unusual characteristics, such as intermixing-control caps at low annealing temperature (650°C) and interdiffusion-promoting caps at high temperatures (≥675°C). We qualitatively compared the degree of intermixing induced by these films by extracting the rate of intermixing and the temperature for ground-state and excited-state convergences. Based on our systematic characterization, we established reference intermixing processes based on seven different dielectric encapsulation materials. The tailored wavelength emission of ∼1060─1200  nm at room temperature and improved optical quality exhibited from intermixed QDs would serve as key materials for eventual realization of low-cost, compact, and agile lasers. Applications include solid-state laser pumping, optical communications, gas sensing, biomedical imaging, green–yellow–orange coherent light generation, as well as addressing photonic integration via area-selective, and postgrowth bandgap engineering.

Paper Details

Date Published: 16 October 2015
PDF: 10 pages
Opt. Eng. 54(10) 107107 doi: 10.1117/1.OE.54.10.107107
Published in: Optical Engineering Volume 54, Issue 10
Show Author Affiliations
Hala H. Alhashim, King Abdullah Univ. of Science and Technology (Saudi Arabia)
Mohammed Zahed Mustafa Khan, King Abdullah Univ. of Science and Technology (Saudi Arabia)
Mohammed A. Majid, King Abdullah Univ. of Science and Technology (Saudi Arabia)
Tien K. Ng, King Abdullah Univ. of Science and Technology (Saudi Arabia)
Boon S. Ooi, King Abdullah Univ. of Science and Technology (Saudi Arabia)


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