In-situ X-ray diffraction study of InAs/GaAs(001) quantum dot growth

Abstract

Molecular beam epitaxial (MBE) growth of InAs/GaAs(OOl) quantum dots and their annealing after deposition were investigated by grazing-incidence X-ray diffraction using a diffractometer integrated with an MBE apparatus. Use of synchrotron radiation and a twodimensional X-ray detector enabled X-ray diffraction intensity mapping in the reciprocal lattice space at a rate of less than 10 s per frame. Results suggest that the degree of alloying that depends on the growth temperature has a strong influence on the structural evolution during annealing.

Structural Changes Caused by Quenching of InAs/GaAs(001) Quantum Dots

“…At this quench rate, however, dislocated islands were still formed in a similar way to the sample cooled at a rate of 20 K/min. The authors' past study showed that dislocated islands tended to be formed at a substrate temperature of 450 C. 19) Hence, the observed dislocated islands are likely to be formed when the substrate temperature passed through 450 C. They are formed so quickly in a narrow temperature range that the quenching rates investigated in the present work did not make a difference.…”

“…Recently, we have developed an X-ray diffraction technique that allows for real-time monitoring of the molecular-beam epitaxial (MBE) growth of InAs/GaAs(001) QDs. [17][18][19] Furthermore, we have shown that the structural properties characterized by in situ X-ray diffraction closely correlate with the optical properties measured by photoluminescence spectroscopy. 20) This X-ray technique provides us with a unique opportunity to investigate the QD structural changes, which are possibly caused by quenching.…”