The properties of electronic defects and their relation to structural defects are of high relevance for $\mathrm{CuInS}{\mathrm{e}}_2$ photovoltaic absorbers. Here, we use Raman scattering and steady-state photoluminescence to study the intrinsic optoelectronic properties of near-stoichiometric $\mathrm{CuInS}{\mathrm{e}}_2$ samples with a lateral composition gradient around the Cu saturation point. Apart from a well-known shallow defect band at 0.97 eV, we also observe a deep defect band at 0.8 eV, which is not discernable in photoluminescence spectra at lower temperatures. The preparation of a laterally graded sample with a very precise relative composition range by in situ process control allows for a measurement of a significant decrease of the photoluminescence emission yield at the Cu-poor/Cu-rich transition on a very narrow composition scale. Possible assignments of the bands to structural point defects are discussed.

中文翻译：

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接近化学计量比的CuInSe2薄膜的辐射复合特性

电子缺陷的性质及其与结构缺陷的关系与 $\mathrm{铜铟锡}{\mathrm{Ë}}_2$光伏吸收器。在这里，我们使用拉曼散射和稳态光致发光来研究近化学计量的内在光电特性$\mathrm{铜铟锡}{\mathrm{Ë}}_2$样品在Cu饱和点附近具有横向成分梯度。除了众所周知的0.97 eV的浅缺陷带以外，我们还观察到0.8 eV的深缺陷带，这在较低温度下的光致发光光谱中无法辨别。通过原位过程控制制备具有非常精确的相对组成范围的横向渐变样品，可以在非常窄的组成范围内测量在贫铜/富铜过渡处光致发光发射率的显着降低。讨论了带对结构点缺陷的可能分配。