Real time during growth metrology and assessment of kinetics of epitaxial quantum dots by RHEED

Abstract

The ability to control their shape and size and reproducibility of epitaxial quantum dots is considered as key to the performance of many advanced photovoltaic devices. We demonstrated the possibility of extracting real time using reflection high energy electron diffraction (RHEED), the average dot-size, dot-facet orientations and dot densities. Here and within the framework of the synthesis of archetype InAs/GaAs quantum dot system we have undertaken a systematic study as a function of growth parameters of the evolution of dot sizes distributions and facet orientation and show the ability of the technique to monitor facetldot asymmetries.

Machine-learning-assisted and real-time-feedback-controlled growth of InAs/GaAs quantum dots

“…So, we assigned the "low" label to densities below 1 × 10 10 cm −2 , the "middle" label to densities ranging from 1 × 10 10 cm −2 to 4 × 10 10 cm −2 . As the density exceeds 4 × 10 10 cm −2 , the spot features become more rounded and show higher brightness, we labeled densities exceeding 4 × 10 10 cm −2 as "high" (see Supplementary Information for RHEED characteristics of QDs with different labels, S1) [31][32][33] . Fig.…”