Facet formation of uniform InAs quantum dots by molecular beam epitaxy

Self-assembled quantum dots (QDs) formed during the Stranski-Krastanov (SK) growth has been expected for applications to optoelectronic devices. However, the formation mechanism of the SK QDs has not been understood clearly Recently, we have reported about self size-limiting (SSL) behavior of the InAs 3-dimensional (3D) islands during the SK growth. The SSL process is due to a stable facet formation and plays an important role of the fabrication of uniform QDs. The SSL growth of the SK dots occurs under relatively low arsenic pressure and low growth rate conditions. From these results, we successfully achieved uniform InAs QDs, which revealed a narrow photoluminescence (PL) linewidth of less than 20 meV. In this study, the facet formation of the uniform InAs QDs was investigated in detail by using reflection high-energy electron-beam diffraction (RHEED) and atomic force microscope (AFM). Obtained results clarified the SSL feature during the formation of the SK 3D dots.