Surface atomic processes during flow-rate modulation epitaxy

Flow-rate modulation epitaxy is the MOCVD-based version of migration-enhanced epitaxy which has been developed to grow atomically flat surfaces and interfaces of III–V compound semiconductors. This method has additional advantages relating to the controllability of the growth process. During flow-rate modulation epitaxy, undesirable gaseous reactions are avoided between group III and group V source gases, and the initial surface condition for every layer growth is precisely controlled. This method has also proved useful for the selective epitaxy of AlGaAs and for the fabrication of low-dimensional structures surrounded by sharp crystal facets. By utilizing these advantages, hexagonal prism-shaped AlGaAs/GaAs dots were successfully grown on patterned (111)B substrates. Each dot lased at an extremely low threshold indicating the desirable effect of flow-rate modulation epitaxy.