Abstract
We grew GaAs crystals using a gradual cooling method aboard the German Spacelab mission D-2. Surfaces of GaAs substrates attached with Ga dissolved into the Ga by heating to 850℃ using an isothermal heating furnace. After that the temperature was gradually decreased to grow GaAs on the undissolved substrate surfaces. By using our original sample setup which eliminated free surfaces from the Ga solution, diffusion controlled convection-free growth was achieved under microgravity. Surface roughness of space-grown crystals was much smaller than that of earth-grown reference samples. This is due to annihilation of macrosteps during growth in space. We discuss macrostep annihilation in an isothermal system.
