MOVPE生长GaN薄膜的表面吸附和扩散研究

发布时间：2018-04-27 18:49

本文选题：GaN + MOVPE　；参考：《人工晶体学报》2017年05期

【摘要】：利用量子化学计算方法,对MOVPE生长GaN薄膜的表面反应进行研究。特别针对反应前体GaCH_3(简称MMG)在理想、H覆盖和NH_2覆盖GaN(0001)面的吸附和扩散进行计算分析。通过建立3×3超晶胞模型,优化计算了MMG在三种不同覆盖表面的稳定吸附位、吸附能和电子布居,搜寻了MMG在稳定吸附位之间的扩散能垒。计算结果表明:对于三种表面,MMG的稳定吸附位均为T4位和H3位,H3位比T4位略微稳定。MMG在NH_2覆盖表面吸附能最大,在H覆盖表面吸附能最小,在理想表面吸附能居中。MMG中的Ga与不同的表面原子形成的化学键的键强的大小顺序为:Ga-NGa-GaGa-H。相比于理想表面和H覆盖表面,MMG在NH_2覆盖表面的扩散能垒最大,因此表面过量的NH_2会抑制MMG的扩散。
[Abstract]:The surface reaction of GaN films grown by MOVPE was studied by quantum chemical calculation. The adsorption and diffusion of the precursor GaCH_3 (MMG), H covering and NH_2 covered GaN (0001) surface were calculated and analyzed. The stable adsorption sites of MMG on three different covering surfaces were optimized by establishing a 3 x 3 supercellular model. The adsorption energy and electron cloth live and search for the diffusion energy barrier between MMG at stable adsorption sites. The results show that the stable adsorption sites of MMG are both T4 and H3 on three kinds of surfaces. The H3 position is slightly stable to T4 position and the adsorption energy of.MMG on the surface of NH_2 is the largest, and the adsorption energy on the H covered surface is the smallest, and the Ga on the ideal surface to adsorb the middle.MMG is on the ideal surface. The order of the bond strength of the chemical bonds formed by different surface atoms is that compared to the ideal surface and the H covered surface, the diffusion energy barrier of MMG on the surface of the NH_2 is maximum, so the excess NH_2 on the surface will inhibit the diffusion of the MMG.

【作者单位】：江苏大学能源与动力工程学院;
【基金】：国家自然科学基金(61474058) 江苏省普通高校研究生科研创新计划项目(CXLX11_0573)
【分类号】：O614.371;TB383.2

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