Biomedical Engineering Reference
In-Depth Information
Fig. 2.3
Formation mechanism of InP ring-shaped QDMs by droplet epitaxy together with strain
relaxation due to lattice mismatching of InP/InGaP
2.3
Experimental Works on Droplet Epitaxy of InP
Ring-Shaped QDMs
InP ring-shaped QDMs are created by the droplet epitaxy technique. GaAs(0 0 1)
substrate is used as the starting material. The GaAs wafer surface is cleaned by
heating at 450
◦
C for 1 h in the introduction chamber of MBE machine to eliminate
the moisture. Then, the GaAs substrate is transferred to the growth chamber for
surface oxide desorption under As pressure with BEP of 6
10
−
6
To r r at slow
ramping of substrate temperature up to 610
◦
C. After the oxide desorption process,
GaAs surface becomes rough. It is necessary to grow 300 nm thick GaAs buffer
layer on top to provide smooth GaAs surface for further MBE growth. Now, the
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