1989, 17. (d) Felix, A. M.; Heimer, E. P.; Wang, C.-T.; Lambros, T.-J.; Fournier, A.; Mowles, T. F.; Maines, S.; Campbell, R. M.; Wegrzynshi, B. B.; Toome, V.; Fry, D.; Madison, V. Int.

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The future of solid-state lighting relies on how the performance parameters will be improved further for developing high-brightness light-emitting diodes. Eventually, heat removal is becoming a crucial issue because the requirement of high brightness necessitates highoperating current densities that would trigger more joule heating. Here we demonstrate that the embedded graphene oxide in a gallium nitride light-emitting diode alleviates the selfheating issues by virtue of its heat-spreading ability and reducing the thermal boundary resistance. The fabrication process involves the generation of scalable graphene oxide microscale patterns on a sapphire substrate, followed by its thermal reduction and epitaxial lateral overgrowth of gallium nitride in a metal-organic chemical vapour deposition system under one-step process. The device with embedded graphene oxide outperforms its conventional counterpart by emitting bright light with relatively low-junction temperature and thermal resistance. This facile strategy may enable integration of large-scale graphene into practical devices for effective heat removal.

A regular solution model for the difference of the chemical free energy between ␥ and phases during ␥ → martensitic transformation in the Fe-Mn binary system has been reexamined and partly modified based on many articles concerning the M s and A s temperatures of Fe-Mn alloys. Using the regular solution model, the measured M s temperatures, and a thermodynamic model for the stacking fault energy (SFE) of austenite (␥), the driving force for ␥ → martensitic transformation, and the SFE of ␥ have been calculated. The driving force for ␥ → martensitic transformation increases linearly from Ϫ68 to Ϫ120 J/mole with increasing Mn content from 16 to 24 wt pct. The SFE of ␥ decreases to approximately 13 at. pct Mn and then increases with increasing Mn content, which is in better agreement with Schumann's result rather than Volosevich et al.'s result.

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