1. Fabrication of Ge quantum dot circle on masked Si substrate
Qijia Cai, Peixuan Chen, Zhenyang Zhong, Zuimin Jiang, Fang Lu* and Zhenghua An
Surface Physics Laboratory, Laboratory of Advanced Materials, Fudan University, PRC
* address:
Motivation
Electron Beam Lithography (EBL)
A novel circularity placement structure of germanium quantum dots has been fabricated by combining techniques including electron beam lithography, wet etching solution and molecular beam epitaxy. It was observed that both pattern and growth parameters affect the morphology of quantum dot molecular. The experimental result indicates the possibilities to investigate properties of quantum dot molecular and single quantum dot.
Traditional fabrication of quantum dots
(shape, size, composition, location distribution, lateral coupling)
Schematic diagram
Single quantum dot (SQD)
Quantum dot array (QDA)
Patterned quantum dot (PAQD)
Patterned Substrate
PAQD Growth
Electrode Contact
Measurements
Molecular Beam Epitaxy (MBE)
EBL、Etch
MBE
Evaporation
Optical diffraction of pattern substrate shows good periodicity.
a) Quantum dot grown on flat substrate shows random placement
b) Quantum dots grown on pattern substrate without oxidation shows almost random placement except some big clusters
Conclusion:
A circle like quantum dots arrangement structure has been fabricated by combining techniques including electron beam lithography, wet etching solution and molecular beam epitaxy. The morphology of quantum dot was affected by both pattern and growth parameters. Experimental result shows the possibilities to investigate properties of quantum dot molecular and single quantum dot under precisely pattern and growth parameters control.
Diameter = 100 nm, height = 27 nm