节点文献
AlN-MOCVD生长中气相寄生反应路径
Gas-phase parasitic reaction pathways in AlN-MOCVD growth
【摘要】 利用量子化学的密度泛函理论,研究用于制备紫外光电器件的AlN薄膜在MOCVD生长中的气相寄生反应,计算与气相纳米粒子相关的3种主要多聚物[DMAlNH2]2,[MMAlNH]2,[MMAlNH]3与NH3的反应路径.通过对比不同温度下反应前后的吉布斯自由能差ΔG以及过渡态的活化自由能ΔG*,判断反应发生的方向和概率.结果表明:[DMAlNH2]2存在2条竞争路径,当T<749 K时,反应走[DMAlNH2]2与NH3的双分子反应路径,产物为[Al（NH2）3]2;当T>749 K时,反应趋向于活化自由能更低的、脱去CH4生成[MMAlNH]2的分子内反应路径.[MMAlNH]2,[MMAlNH]3与NH3极易发生双分子反应,脱去CH4,生成更稳定的气相产物[AlNHNH2]2和[AlNHNH2]3.[Al（NH2）3]2,[AlNHNH2]2,[AlNHNH2]3很可能是AlN-MOCVD气相寄生反应的末端粒子,也是AlN生长表面反应和纳米粒子的重要前体.
【Abstract】 The density functional theory（DFT） of quantum chemistry was used to study the gas-phase parasitic reactions in AlN-MOCVD growth for UV optoeletronic devices. The reaction pathways of three oligomers of [DMAlNH2]2, [MMAlNH]2 and [MMAlNH]3 with NH3 were investigated, which were related with gaseous nano-particle generation. By comparing the Gibbs free energy difference of ΔG and transition state barrier of ΔG*, the direction and probability of the related reactions were determined. The results show that there are two competition pathways for [DMAlNH2]2. When T is less than 749 K, the reaction path is dominated by bimolecular reaction with [Al（NH2）3]2 as the product. When T is more than 749 K, it is dominated by intramolecular reaction with [MMAlNH]2 as the product, since the reactions always take the path with lower energy barrier. The other two oligomers of [MMAlNH]2 and [MMAlNH]3 both tend to the bimolecular reaction with NH3 to form the more stable gas products of [AlNHNH2]2 and [AlNHNH2]3 with CH4 elimination. The [Al（NH2）3]2, [AlNHNH2]2 and [AlNHNH2]3 are probably the end gas precursors for surface reactions and for nanoparticle generation in AlN-MOCVD process.
【Key words】 AlN； MOCVD； density functional theory(DFT)； oligomers； parasitic reaction；
- 【文献出处】 江苏大学学报(自然科学版) ,Journal of Jiangsu University(Natural Science Edition) , 编辑部邮箱 ,2020年05期
- 【分类号】TN304.055
- 【被引频次】1
- 【下载频次】74