In this work, we demonstrate that β-Ga2O3 shows orientation-dependent polarized photoluminescence (PL) emission and give a comprehensive insight into gallium oxide's PL spectral properties. We characterized the polarization and spectral dependencies of both the incident and emitted light for (−201) unintentionally doped (UID) as well as (−201) and (010) Sn-doped and Fe-doped crystals. We observed for UID and Sn-doped samples that the electron to self-trapped hole and native defect-related emission bands are linearly polarized with polarized emission intensities ordered as E || c (and c*) > E || a (and a*) > E || b. Furthermore, the spectral shape of emission does not change between the UID and Sn-doped samples; instead, the Sn-doping quenches the total PL spectral intensity. For Fe-doped samples, polarized red emission caused by unintentional Cr3+ doping generates emission intensities ordered E || b > E || c (and c*) > E || a (and a*). It is also observed that in some circumstances, for some doped crystals, the PL spectra can show variations not only in intensity but also in spectral shape along different polarization directions. As an example, the PL emission band for emission along c is blueshifted relative to that along a in Sn-doped β-Ga2O3.

中文翻译：

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Sn、Fe 和无意掺杂的 β-Ga2O3 的偏振光致发光

在这项工作中，我们证明 β-Ga2O3 显示出方向相关的偏振光致发光 (PL) 发射，并全面了解氧化镓的 PL 光谱特性。我们表征了 (−201) 无意识掺杂 (UID) 以及 (−201) 和 (010) Sn 掺杂和 Fe 掺杂晶体的入射光和发射光的偏振和光谱依赖性。我们观察到，对于 UID 和 Sn 掺杂样品，电子到自捕获空穴和本机缺陷相关的发射带是线性偏振的，偏振发射强度顺序为 E || c(和c*)＞E|| a(和a*)＞E|| b. 此外，UID 样品和 Sn 掺杂样品之间的发射光谱形状没有变化；相反，Sn 掺杂会淬灭总 PL 光谱强度。对于 Fe 掺杂样品，无意的 Cr3+ 掺杂引起的偏振红光发射会产生顺序为 E || 的发射强度。b> E|| c(和c*)＞E|| 一个（和一个*）。还观察到，在某些情况下，对于某些掺杂晶体，PL 光谱不仅可以显示出强度的变化，而且可以显示沿不同偏振方向的光谱形状的变化。例如，在 Sn 掺杂的 β-Ga2O3 中，沿 c 发射的 PL 发射带相对于沿 a 的发射带发生蓝移。