摘要
利用量子化学的密度泛函理论,对MOVPE生长Al N的气相反应路径进行理论计算和分析,特别针对氨基物DMAl NH2形成后的多聚反应、多聚物消去甲烷反应、以及温度的影响关系进行研究。通过对不同反应路径的吉布斯自由能和反应能垒的计算,分别从热力学和动力学上确定最可能的末端气相反应前体。研究发现,氨基物通过与NH3的双分子碰撞,很容易越过较低的能垒,形成稳定的Al(NH2)3。在385 K<T<616 K,三聚物(DMAl NH2)3消去CH4变成(MMAl NH)3的反应容易发生。在641 K<T<1111 K,二聚物(DMAl NH2)2消去CH4变成(MMAl NH)2的反应容易发生。而(MMAl NH)2、(MMAl NH)3继续消去CH4生成(Al N)2、(Al N)3的反应,由于吉布斯自由能差都大于零,而且能垒也很大,故很难发生。因此,在Al N的MOVPE过程中,Al(NH2)3、(MMAl NH)2和(MMAl NH)3是最可能的三种末端气相反应前体,它们将决定Al N的表面反应生长。
By density functional theory study,the gas reaction mechanism in AIN MOVPE growth is explored,especially the oligomerization and the following CH4 elimination after the amide formation and the temperature effect.By calculations of the Gibbs free energies and the energy barriers at different temperatures along the three reaction paths after the amide DMA1NH2 formation,the most probable end gas products are determined both thermodynamically and kinetically.By bimolecular reactions of DMA1NH2 with NH3,the formation of stable Al(NH2)3 is thermodynamically favorable with low energy barrier.When 385 K<r<616 K,the formation of(MMA1NH)3 is favorable with CH4 elimination from the trimer.When 641 K<T<1111 K,the formation of(MMA1NH)2 is favorable with CH4 elimination from the dimer,while the further elimination of CH4 from(MMA1NH)2 and(MMA1NH)3 to form(AIN)2 and(A1N)3 are thermodynamically unfavorable.Therefore,it can be concluded that Al(NH2)3,(MMA1NH)2 and(MMA1NH)3 are the three most probable end gas products in AIN MOVPE process,which will provide the surface reactions of AIN growth.
作者
张莲
张红
左然
ZHANG Lian;ZHANG Hong;ZUO Ran(School of Energy and Power Engineering,Jiangsu University,Zhenjiang 212013,China)
出处
《人工晶体学报》
EI
CAS
CSCD
北大核心
2018年第3期481-488,共8页
Journal of Synthetic Crystals
基金
国家自然科学基金(61474058)
