Effect of strain on GaN exciton spectra
Effect of strain on GaN exciton spectra
复制标题
应变对 GaN 激子光谱的影响
DOI：
10.1088/0268-1242/11/7/009
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
J. Orton
中科院分区：
文献类型：
--
作者：
J. Orton
绝大多数氮化镓外延膜生长在晶格和热膨胀不匹配的衬底上，结果是明显的应变。这种效应最容易通过测量光致发光光谱中的激子能量来监测，本文比较了在蓝宝石衬底上生长的一系列异质外延样品中同外延薄膜中自由激子能量的已发表数据，所有薄膜都具有六角形（细锌矿）结构。我们观察到，应变导致B和C激子的分离显著增加，而a， B的分离相对不受影响，并根据Hopfield为CdS和其他II - VI化合物的非常相似的情况开发的准立方带结构模型来解释这一点。在该模型的限制下，由于自旋轨道和晶体场分裂参数是可互换的，激子能量的解释存在歧义。考虑应变效应消除了这种模糊性，使我们能够推导出未应变的同外延样品的meV和meV值，这与Dingle等人基于相对强度测量的早期估计一致。
The large majority of GaN epitaxial films have been grown on substrates which show both lattice and thermal expansion mismatch and, as a result, are significantly strained. The effect is most readily monitored by measuring exciton energies in photoluminescence spectra, and this paper compares published data on free exciton energies in a homoepitaxial film with a range of heteroepitaxial samples grown on sapphire substrates, all the films having the hexagonal (wurtzite) structure. We observe that strain results in a marked increase in separation of the B and C excitons while leaving the A, B separation relatively unaffected, and interpret this in terms of the quasi-cubic band structure model developed by Hopfield for the very similar case of CdS and other II - VI compounds. Within the limits of this model, there is an ambiguity in the interpretation of exciton energies which depends on the fact that the spin - orbit and crystal field splitting parameters are interchangeable. Consideration of strain effects removes this ambiguity and allows us to derive values of meV and meV for the unstrained homoepitaxial sample, consistent with the earlier estimates of Dingle et al based on relative intensity measurements.
影响因子：
4
作者：
NAKAMURA, S;MUKAI, T;SENOH, M
通讯作者：
SENOH, M