New compositionally-ordered GeSi nanodots fabricated with 1250 keV electrons

摘要

Transformation of uniformly strained GexSi1-x layers into GeSi dots of 3 - 7 nm which are compositionally ordered by one or concurrently two sets of {111} planes was carried out for the first time under non-equilibrium conditions induced by 1.25 MeV electron irradiation at T_c >= 200 deg C in the high voltage electron microscope (JEM-ARM1300S). This microscope installed in the KBSI is characterized by an excellent point-to-point resolution of 0.12 nm allowing obtaining detailed information on chemical ordering at specific parameters of defocus (-800 A) and crystal thickness (200-250 A) determined by extensive HRTEM image simulation for the ordered dots.