Highly Tensile-Strained Self-Assembled Ge Quantum Dots on InP Substrates for Integrated Light Sources
Journal article, 2021
Highly tensile-strained Ge quantum dots (TS-Ge-QDs) emitting structures with different size were successfully grown on InP substrates by molecular beam epitaxy. Dislocation-free TS-Ge-QDs were observed by transmission electron microscopy. Finite element modeling indicates a maximum tensile strain of 4.5% in the Ge QDs, which is much larger than the required strain to achieve direct band gap conversion of Ge based on theoretical prediction. Photoluminescence (PL) from a direct band-gap-like transition of TS-Ge-QDs with a peak energy of 0.796 eV was achieved and confirmed by the etch depth-dependent PL, temperature-dependent PL, and excitation-power-dependent PL. In addition, a strong defect-related peak of 1 eV was observed at room temperature. The band structure of the TS-Ge-QDs emitting structures was calculated to support the experimental results of PL spectra. Achieving PL from direct band-gap-like transitions of TS-Ge-QDs provides encouraging evidence of this promising highly tensile strained semiconductor-nanostructure-based platform for future photonics applications such as integrated light sources.
quantum dots
photoluminescence
tensile strain
quantum confinement effects
self-assembled growth
germanium
Author
Q. Chen
Chinese Academy of Sciences
Nanyang Technological University
Liyao Zhang
University of Shanghai for Science and Technology
Y Song
Chinese Academy of Sciences
X Chen
Chinese Academy of Sciences
Sebastian Koelling
Eindhoven University of Technology
Z. Zhang
Chinese Academy of Sciences
Y Li
Chinese Academy of Sciences
P. M. Koenraad
Eindhoven University of Technology
Jun Shao
Chinese Academy of Sciences
Chuan Seng Tan
Nanyang Technological University
Shu Min Wang
Chalmers, Microtechnology and Nanoscience (MC2), Photonics
Chinese Academy of Sciences
Qian Gong
Chinese Academy of Sciences
ACS Applied Nano Materials
25740970 (eISSN)
Vol. 4 1 897-906Subject Categories
Atom and Molecular Physics and Optics
Nano Technology
Condensed Matter Physics
DOI
10.1021/acsanm.0c03373