High-Temperature Metalorganic Vapor Phase Epitaxial Growth of GaAs/AlGaAs Quantum Structures in Tetrahedral-Shaped Recesses on GaAs (111)B Substrates

GaAs/AlGaAs quantum structures were grown in tetrahedral-shaped recesses (TSRs) on GaAs {111}B substrates at temperatures above 800°C by metalorganic vapor phase epitaxy because quantum dots were expected to be formed at the bottom {111} regions of the TSRs. Observation of cathodoluminescence revealed that GaAs quantum structures with different layer thicknesses were formed at {100} edge regions, {110} and {111}A sidewalls and the {111} bottom and surface regions of the TSR. Growth on the {111}B surface region between TSRs was clearly observed for the sample grown at 850°C. As the growth temperature was raised above 850°C, the photoluminescence intensity on the {111}B surface increased whereas that on the {001} edge regions and {111}A sidewall regions decreased. With an increase in well thickness, the luminescence from the bottom and edge regions was simultaneously observed. A 50 Å-thick quantum well was formed on the small bottom region. From scanning electron microscope observation, the lateral size of the region was 550 Å.