Direct experimental determination of the spontaneous polarization of GaN
Direct experimental determination of the spontaneous polarization of GaN
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DOI：
10.1103/physrevb.86.081302
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发表时间：
2012-08-09
影响因子：
3.7
通讯作者：
Geelhaar, Lutz
中科院分区：
文献类型：
--
作者：
Laehnemann, Jonas;Brandt, Oliver;Geelhaar, Lutz
我们提出了一种由纤锌矿半导体中不同类型的层错所束缚的激子的发射能量来确定这些半导体的自发极化P-SP的普遍方法。利用显微光致发光和阴极发光光谱，我们观察到了无应变GaN微晶中本征和非本征堆积缺陷的发射线。通过将与这些层错相关的极化薄层电荷处理为平板电容器，无需附加假设，即可从观察到的跃迁能得到P-SP。自洽Poisson-Schrodinger计算，辅以密度泛函理论计算的微观静电势，得到了几乎相同的P-sp值。GaN的P-sp值为-0.022+/-0.007 C/m(2)。
We present a universal approach for determining the spontaneous polarization P-sp of a wurtzite semiconductor from the emission energies of excitons bound to the different types of stacking faults in these crystals. Employing microphotoluminescence and cathodoluminescence spectroscopy, we observe emission lines from the intrinsic and extrinsic stacking faults in strain-free GaN microcrystals. By treating the polarization sheet charges associated with these stacking faults as a plate capacitor, P-sp can be obtained from the observed transition energies with no additional assumptions. Self-consistent Poisson-Schrodinger calculations, aided by the microscopic electrostatic potential computed using density-functional theory, lead to nearly identical values for P-sp. Our recommended value for P-sp of GaN is -0.022 +/- 0.007 C/m(2).