Pseudomorphic ZnO‐based heterostructures: From polar through all semipolar to nonpolar orientations
Pseudomorphic ZnO‐based heterostructures: From polar through all semipolar to nonpolar orientations
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赝晶 ZnO 基异质结构：从极性到所有半极性到非极性取向
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
J. Zúñiga
中科院分区：
文献类型：
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作者：
M. Grundmann;J. Zúñiga
我们计算了假晶纤锌矿 Mg x Zn 1−x O/ZnO 和 Cd x Zn 1−x O/ZnO 异质结构中的应变和应力状态以及极化作为 c 轴和外延方向之间极角 θ 的函数。 (Cd,Zn)O/ZnO 的性质与 (In,Ga)N/GaN 和 (Al,Ga)N/GaN 系统相似。 (Mg,Zn)O/ZnO 代表一种独特的情况，因为晶格常数 ∂a/∂x 和 ∂c/∂x 的变化符号相反。结果包括： (i) 对于接近 (112‾2) 的半极性生长面，外延层应变能的最小值在 0∘ 和 90∘ 之间； (ii) 对于非极性生长 ( θ=90∘ )，外延方向的应变接近于零；面内偏振度较大（与极地情况相比）； (iii) 沿生长方向的压电极化在 0 ∘ 和 180 ∘ 之间只有一个零（在 θ=90∘ 处）。我们还给出了柔量的各向同性近似内有用的分析公式。
We calculate the strain and stress state and the polarization in pseudomorphic wurtzite Mg x Zn 1−x O/ZnO and Cd x Zn 1−x O/ZnO heterostructures as a function of the polar angle θ between the c‐axis and the epitaxial direction. (Cd,Zn)O/ZnO behaves qualitatively similar to the systems (In,Ga)N/GaN and (Al,Ga)N/GaN. (Mg,Zn)O/ZnO represents a unique case since the signs of the change of lattice constants ∂a/∂x and ∂c/∂x are opposite. Among the consequences are: (i) the epilayer strain energy has a minimum between 0∘ and 90∘ for semipolar growth plane close to (112‾2) ; (ii) for nonpolar growth ( θ=90∘ ) the strain in the epitaxial direction is close to zero; and the in‐plane polarization is large (comparable to the polar case); and (iii) the piezoelectric polarization along the growth direction has only one zero (at θ=90∘ ) between 0 ∘ and 180∘ . Also we give useful analytical formula within an isotropic approximation for the compliances.