Fundamental Research on Nitride Metalirgy-New Rovte for GaN Synthesis-

GaN是一种重要的功能材料，因为它具有发射短波长光的能力。尽管在中等温度下氮气氮化金属镓在热力学上是可行的，但在常压下氮化实际上是困难的，因为初始反应导致GaN层，这形成了进一步反应的有效势垒。在本文中，我们证明了在氮气渗氮过程中，Li_3GaN_2这样的复合氮化物可以作为镓合金渗氮的反应媒介。GaN是在没有与氮气直接物理接触的情况下合成的。通过对Li_3GaN_2热力学性质的测定，证实了该反应的可行性，并利用建立的等温化学势图讨论了该反应的机理。例如，用原电池测量电动势，确定了Li3GaN_2的生成吉布斯能，并讨论了GaN_i Li_3GaN_2两相平衡下氮化学势的势能范围。提出了一种分析介质法合成GaN可行性的新方法。

GaN is an important functional material because of its ability to emit short wave length light. Although nitriding of gallium metal by nitrogen gas is thermodynamically feasible at moderate temperatures, it is practically difficult under a normal pressure because incipient reaction leads to a layer of GaN which forms an effective barrier to further reaction. In this communication, we show that a complex nitride such as Li_3GaN_2 can act as a reaction mediator during nitriding of gallium alloys with nitrogen gas. GaN is synthesized without direct physical contact between gallium and nitrogen gas. Feasibility of this reaction is confirmed by measuring thermodynamic properties of Li_3GaN_2, and mechanism of this reaction is discussed using an isothermal chemical potential diagram constructed from the results of the present study. For example, the Gibbs energy of formation of Li_3GaN_2 is determined by measuring electromive force measurement using galvanic cell, and potential range of nitrogen chemical potential under GaN I Li_3GaN_2 two phase equilibrium is discussed. New approach for analyzing the feasibility of GaN synthesis through a mediator is demonstrated.