Liu Dongdong, Zhang Zhenyu, Chen Leilei, Wang Dong, Cui Junfeng, Chang Keke, Guo Dongming
Key Laboratory for Precision and Non-Traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian 116024, China.
Nanoscale. 2021 Apr 21;13(15):7169-7175. doi: 10.1039/d1nr00447f. Epub 2021 Apr 6.
Phase transformations occurring in a solid govern the structural and physical properties significantly. Nevertheless, deformation-induced phase transition in a soft-brittle solid has not been demonstrated yet. Soft-brittle cadmium zinc telluride (CZT) based instruments have produced technological breakthroughs in the semiconductor industry, and therefore their phase transformations have been widely investigated during the past 60 years. In this study, in situ transmission electron microscopy (TEM) nanoindentation was performed on CZT, and it was found that no brittle fracture occurred at a peak load of 41.9 μN, corresponding to a stress of 1.75 GPa. A new nanostructure induced by in situ TEM nanoindentation was observed, consisting of a single crystal, slip bands, stacking faults, a superlattice, a new tetragonal phase, and Moiré fringes. The new tetragonal phase was formed by partial Cd and Te atoms in the (111[combining macron]) plane slipping along the [1[combining macron]21[combining macron]] orientation, which was elucidated by ab initio simulations. It belongs to a tetragonal crystal system, and the lattice distances along the X and Y axes were 0.382 and 0.376 nm, respectively. Our findings provide new insights into the deformation-induced phase transformation for a soft-brittle solid, and have application potential in solar cells, radiation detectors, and medical imaging, quantum, flexible electronic and optoelectronic devices.
固体中发生的相变对其结构和物理性质有重大影响。然而，软脆固体中的变形诱导相变尚未得到证实。基于软脆碲镉锌（CZT）的仪器在半导体行业取得了技术突破，因此在过去60年里对其相变进行了广泛研究。在本研究中，对CZT进行了原位透射电子显微镜（TEM）纳米压痕试验，发现在41.9 μN的峰值载荷下未发生脆性断裂，对应应力为1.75 GPa。观察到一种由原位TEM纳米压痕诱导产生的新纳米结构，它由单晶、滑移带、堆垛层错、超晶格、一种新的四方相和莫尔条纹组成。新的四方相是由（111[上加横线]）平面中的部分Cd和Te原子沿[1[上加横线]21[上加横线]]取向滑移形成的，这一点通过第一性原理模拟得到了阐明。它属于四方晶系，沿X轴和Y轴的晶格间距分别为0.382和0.376 nm。我们的研究结果为软脆固体的变形诱导相变提供了新的见解，在太阳能电池、辐射探测器、医学成像、量子、柔性电子和光电器件等方面具有应用潜力。
