Czochralski growth of Te–rich SexTe1−x crystals

Abstract

Single crystals of tellurium-rich SexTe1−x alloys have been grown by the Czochralski method for x < 0.16. A double-crucible was used to contain the melt, which eliminated scum on the liquid surface, enabling crystals to be grown with higher selenium concentrations than previously obtained. The inner graphite vessel of the crucible not only drew scum-free liquid from the quartz outer container, but also acted as a susceptor for the radio-frequency (r.f.) heating, producing more stable convection in the melt. With this method, single crystals of good quality, as indicated by Laue patterns, were obtained from melts containing up to 30 at.% selenium. The concentrations of selenium in the crystals, as determined by electron-probe microanalysis (EPMA), were about half those in the corresponding melts, in agreement with the Te-rich end of the phase diagram. It was also found that single crystals of Te-rich SexTe1−x could be grown equally well in pulling directions both parallel and perpendicular to the c axis.