First-Principles Calculation and Experimental Investigation of a Three-Atoms-Type MXene V<sub>2</sub>C and Its Effects on Memristive Devices
Xintong Chen, Yu Wang, Daqi Shen, Miaocheng Zhang, Yize Zhao, Lvyang Zhou, Qi Qin, Qiangqiang Zhang, Nan He, Min Wang, Ertao Hu, Xiaoyan Liu, Jianguang Xu, Lei Wang, Yi Tong
Abstract
MXene is a hot family of transition metal carbides or nitrides demonstrating promising potentials in the fields of batteries, supercapacitors, and memristive devices. One of MXenes, i.e., five-atoms-type MXene (Ti <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ), has been reported to fabricate memristive devices and show resistive switching. However, MXene has another big group of three-atoms-type rather than five-atoms-type based on fundamental chemical structure. Besides, the group of three-atoms-type MXene is rarely investigated to fabricate memristive devices. Moreover, the effect of three-atoms-type Mxene (i.e., V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> C) on the performance of memristive devices and the physical mechanisms behind have not been explored. In this work, we constructed the lattice structure and compared the fundamental properties of V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> C with Ti <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> using the first-principles calculation. Moreover, the diffusion coefficient and the conductivity of Ag <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> in V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> C and Ti <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> have been checked by the density functional theory (DFT). It can be revealed that V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> C has a more stable atomic structure, a higher conductivity, and a superior diffusion coefficient of Ag <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> in V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> C. In addition, we fabricated memristive devices of the Ag/V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> C/W and Ag/Ti <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /W based on the simulation results for comparison. Next, electrical characteristics of V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> C and Ti <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> of memristive devices were tested including the variation of device-to-device and cycle-to-cycle, the endurance, and the ratio of R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</sub> /R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</sub> . The experimental data indicate that the memristive devices with V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> C have achieved more stable resistive switching behaviors. The results of this work provide a useful guideline and methodology for exploring and determining various types of MXenes in advance of the experimental fabrication of memristive devices.