Exciton photoluminescence and benign defect complex formation in zinc tin nitride,Materials Horizons

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Exciton photoluminescence and benign defect complex formation in zinc tin nitride
Materials Horizons ( IF 12.2 ) Pub Date : 2018-06-27 , DOI: 10.1039/c8mh00415c
Angela N. Fioretti _{1,

2,

3,

4,

5} , Jie Pan _{1,

2,

3,

4} , Brenden R. Ortiz _{2,

4,

5} , Celeste L. Melamed _{1,

2,

3,

4,

5} , Patricia C. Dippo _{1,

2,

3,

4} , Laura T. Schelhas _{4,

6,

7,

8,

9} , John D. Perkins _{1,

2,

3,

4} , Darius Kuciauskas _{1,

2,

3,

4} , Stephan Lany _{1,

2,

3,

4} , Andriy Zakutayev _{1,

2,

3,

4} , Eric S. Toberer _{1,

2,

3,

4,

5} , Adele C. Tamboli _{1,

2,

3,

4,

5}

Affiliation

Emerging photovoltaic materials need to prove their viability by demonstrating excellent electronic properties. In ternary and multinary semiconductors, disorder and off-stoichiometry often cause defects that limit the potential for high-efficiency solar cells. Here we report on Zn-rich ZnSnN₂ (Zn/(Zn + Sn) = 0.67) photoluminescence, high-resolution X-ray diffraction, and electronic structure calculations based on Monte-Carlo structural models. The mutual compensation of Zn excess and O incorporation affords a desirable reduction of the otherwise degenerate n-type doping, but also leads to a strongly off-stoichiometric and disordered atomic structure. It is therefore remarkable that we observe only near-edge photoluminescence from well-resolved excitons and shallow donors and acceptors. Based on first principles calculations, this result is explained by the mutual passivation of Zn_Sn and O_N defects that renders both electronically benign. The calculated bandgaps range between 1.4 and 1.8 eV, depending on the degree of non-equilibrium disorder. The experimentally determined value of 1.5 eV in post-deposition annealed samples falls within this interval, indicating that further bandgap engineering by disorder control should be feasible via appropriate annealing protocols.

中文翻译：

氮化锌锡中的激子光致发光和良性缺陷复合物的形成

新兴的光伏材料需要通过展示出色的电子性能来证明其可行性。在三元和多元半导体中，无序和化学计量失误通常会导致缺陷，从而限制了高效太阳能电池的潜力。在这里我们报告富锌的ZnSnN ₂（Zn /（Zn + Sn）= 0.67）光致发光，高分辨率X射线衍射和基于蒙特卡洛结构模型的电子结构计算。Zn过量和O掺入的相互补偿提供了所需的减少的简并的n型掺杂，但是还导致了化学计量极差且无序的原子结构。因此，值得注意的是，我们仅观察到了分辨良好的激子和浅的供体和受体的近边缘光致发光。基于第一性原理计算，该结果可以通过Zn _Sn和O _N的互钝化来解释。造成电子良性的缺陷。计算的带隙范围在1.4到1.8 eV之间，具体取决于非平衡障碍的程度。实验确定的沉积后退火样品中的1.5 eV值在此间隔内，这表明通过适当的退火方案，通过无序控制进行的进一步带隙工程应该是可行的。

更新日期：2018-08-29

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