Strain-induced polarization in wurtzite III-nitride semipolar layers
Strain-induced polarization in wurtzite III-nitride semipolar layers
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DOI：
10.1063/1.2218385
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发表时间：
2006-07-15
影响因子：
3.2
通讯作者：
Speck, J. S.
中科院分区：
文献类型：
--
作者：
Romanov, A. E.;Baker, T. J.;Speck, J. S.
本文提出了与 GaN 晶格匹配的 InxGa1-xN 和 AlyGa1-yN 层的压电极化的生长方向依赖性。随着在半极性面上生长氮化物基器件的出现，这个主题变得相关起来[A.查克拉博蒂，日本。 J.应用程序。物理学，第 2 部分 44，L945 (2005)]。计算表明，对于与 GaN 晶格匹配的应变 InxGa1-xN 和 AlyGa1-yN 层，压电极化对于非极性取向为零，并且在与 c 平面倾斜约 45 度的另一点处也是如此。零交叉对三元合金层的In或Al含量仅具有非常小的依赖性。随着自发极化的增加，InxGa1-xN 的总极化为零的角度略有增加，但确切的值取决于 In 含量。对于 AlyGa1-yN 失配层，通过将 c 轴取向薄膜的交叉点增加到大约 70 度，自发极化的影响变得很重要。这些计算是使用压电常数和弹性常数的最新且令人信服的值进行的，并应用 Vegard 定律来估计三元 InxGa1-xN 和 AlyGa1-yN 层中的常数。
This paper presents growth orientation dependence of the piezoelectric polarization of InxGa1-xN and AlyGa1-yN layers lattice matched to GaN. This topic has become relevant with the advent of growing nitride based devices on semipolar planes [A. Chakraborty , Jpn. J. Appl. Phys., Part 2 44, L945 (2005)]. The calculations demonstrate that for strained InxGa1-xN and AlyGa1-yN layers lattice matched to GaN, the piezoelectric polarization becomes zero for nonpolar orientations and also at another point approximate to 45 degrees tilted from the c plane. The zero crossover has only a very small dependence on the In or Al content of the ternary alloy layer. With the addition of spontaneous polarization, the angle at which the total polarization equals zero increases slightly for InxGa1-xN, but the exact value depends on the In content. For AlyGa1-yN mismatched layers the effect of spontaneous polarization becomes important by increasing the crossover point to similar to 70 degrees from c-axis oriented films. These calculations were performed using the most recent and convincing values for the piezoelectric and elasticity constants, and applying Vegard's law to estimate the constants in the ternary InxGa1-xN and AlyGa1-yN layers.