Long-term crystal growth under microgravity during the EURECA-1 mission .2. THM growth of sulphur-doped InP

Long-term crystal growth experiments were successfully performed under microgravity conditions during the first flight of the unmanned EURECA-1 mission in the automatic mirror furnace (AMF). Two crystals of sulphur-doped InP with [001] and [111] orientation respectively were grown from indium solution by the travelling heater method (THM). The absence of time dependent buoyancy-driven convection is documented by the lack of type I striations in the space-grown crystals. The sulphur concentration is measured by spatially resolved photoluminescence. As expected, the macrosegregation can be described by a pure diffusion-controlled model which is in good agreement with the findings from the first German spacelab mission D1. Compared to the earth-grown reference samples, both of the space-grown InP crystals show strong disturbances such as inclusions and type II striations. The morphological instabilities are similar to growth disturbances already known from the space-grown MD-ELI-01 from the D1 mission.