Zhu Min, Song Wenxiong, Konze Philipp M, Li Tao, Gault Baptiste, Chen Xin, Shen Jiabin, Lv Shilong, Song Zhitang, Wuttig Matthias, Dronskowski Richard
State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Micro-System and Information Technology, Chinese Academy of Sciences, 200050, Shanghai, China.
Chair of Solid-State and Quantum Chemistry, Institute of Inorganic Chemistry, RWTH Aachen University, 52056, Aachen, Germany.
Nat Commun. 2019 Aug 6;10(1):3525. doi: 10.1038/s41467-019-11506-0.
Doping is indispensable to tailor phase-change materials (PCM) in optical and electronic data storage. Very few experimental studies, however, have provided quantitative information on the distribution of dopants on the atomic-scale. Here, we present atom-resolved images of Ag and In dopants in SbTe-based (AIST) PCM using electron microscopy and atom-probe tomography. Combing these with DFT calculations and chemical-bonding analysis, we unambiguously determine the dopants' role upon recrystallization. Composition profiles corroborate the substitution of Sb by In and Ag, and the segregation of excessive Ag into grain boundaries. While In is bonded covalently to neighboring Te, Ag binds ionically. Moreover, In doping accelerates the crystallization and hence operation while Ag doping limits the random diffusion of In atoms and enhances the thermal stability of the amorphous phase.
掺杂对于在光学和电子数据存储中定制相变材料（PCM）而言不可或缺。然而，极少有实验研究能提供关于掺杂剂在原子尺度上分布的定量信息。在此，我们利用电子显微镜和原子探针断层扫描技术展示了基于SbTe的（AIST）PCM中Ag和In掺杂剂的原子分辨图像。将这些图像与密度泛函理论（DFT）计算及化学键分析相结合，我们明确确定了掺杂剂在再结晶过程中的作用。成分分布证实了In和Ag对Sb的取代，以及过量Ag向晶界的偏析。In与相邻的Te形成共价键，而Ag则形成离子键。此外，In掺杂加速了结晶过程，从而提高了运行速度，而Ag掺杂限制了In原子的随机扩散并增强了非晶相的热稳定性。
