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Conclusion

The calculated maximum Ga amount using the Langmuir equation during distillation at 1360 K and growth at 1160 K was 67.9 g. This calculated value was much higher than 25 g of Ga loss observed. This disagreement was corrected by using the transmission probability by Clausing theory which includes the consideration of the condensation of Ga particles back into melt due to collision between Ga particles inside the crucible. The evaporated amount of Ga assuming the presence of collisions was obtained by applying a receding length of melts over time to the evaporation rate within a cylindrical crucible. Using the correction, the evaporated amount of Ga, 28.9 g was closed to the observed amount of loss, 25 g.

Acknowledgements Support for this research from the W.M. Keck Foundation is gratefully acknowledged. The authors also would like to thank ultra-pure GaAs Keck Project team members at Purdue University.

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