Temperature dependence of the optical energy gap and Urbach’s energy of CuIn5Se8
Temperature dependence of the optical energy gap and Urbach’s energy of CuIn5Se8
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CuIn5Se8 的光学能隙和乌尔巴赫能量的温度依赖性
DOI：
10.1063/1.1405144
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发表时间：
2001
影响因子：
3.2
通讯作者：
Ernesto Antonio Medina Dagger
中科院分区：
文献类型：
--
作者：
C. Rincón;S. Wasim;G. Marín;R. Marquez;L. Nieves;G. S. Pérez;Ernesto Antonio Medina Dagger
采用吸收技术研究了六方结构有序缺陷化合物CuIn5Se8的光学性质。数据分析表明，带隙能量EG在10到300 K之间变化范围为1.23到1.13 eV。发现EG随温度的变化是由于声子和光学声子的贡献，其特征声子能量约为14 meV。吸收限下方的光学吸收系数随光子能量呈指数变化，表明乌尔巴赫尾部的存在。与乌尔巴赫尾部相关的声子能量 hνp 被发现为 53 meV，高于报道的该化合物的最高光学声子模式（约 29 meV）。额外能量的来源归因于低能量形成的结构无序产生的局域模式的贡献。经验关系，之前也用于 1:1:2 和 1:3:5 的其他有序缺陷化合物的情况...
The optical properties of the ordered defect compound CuIn5Se8, which crystallizes in a hexagonal structure, have been studied by the absorption technique. The analysis of the data shows that the band gap energy EG varies from 1.23 to 1.13 eV between 10 and 300 K. It is found that the variation of EG with temperature is due to the contribution of both acoustic and optical phonons with a characteristic phonon energy of about 14 meV. The optical absorption coefficient just below the absorption edge varies exponentially with photon energy indicating the presence of Urbach’s tail. The phonon energy hνp associated with Urbach’s tail, which is found to be 53 meV, is higher than the highest optical phonon mode reported for this compound, which is about 29 meV. The origin of the additional energy is attributed to the contribution of localized modes produced by structural disorder of low energy formation. An empirical relation, also used earlier in the case of 1:1:2 and other ordered defect compounds of the 1:3:5 ...