Engineering Atomic‐Scale Patterning and Resistive Switching in 2D Crystals and Application in Image Processing

Abstract

The ultrathin thickness of 2D layered materials affords the control of their properties through defects, surface modification, and electrostatic fields more efficiently compared with bulk architecture. In particular, patterning design, such as moiré superlattice patterns and spatially periodic dielectric structures, are demonstrated to possess the ability to precisely control the local atomic and electronic environment at large scale, thus providing extra degrees of freedom to realize tailored material properties and device functionality. Here, the scalable atomic‐scale patterning in superionic cuprous telluride by using the bonding difference at nonequivalent copper sites is reported. Moreover, benefitting from the natural coupling of ordered and disordered sublattices, controllable piezoelectricity‐like multilevel switching and bipolar switching with the designed crystal structure and electrical contact is realized, and their application in image enhancement is demonstrated. This work extends the known classes of patternable crystals and atomic switching devices, and ushers in a frontier for image processing with memristors.

Controlled Synthesis of Ultrathin Cu2Te Nanosheets for High-Performance Photodetectors

“…The XRD studies in Figure d show that the peaks in the diffraction patterns of a high-quality Cu 2 Te single crystal can be indexed to (001), (100), and (102) planes, respectively (JCPDS card no. 39-1061), which is in good agreement with the previous reports. ,, The X-ray photoelectron spectroscopy (XPS) is applied to observe the surface chemical composition and elemental bonding configuration of obtained Cu 2 Te nanosheets. Figure e displays the Cu 2p and Te 3d binding energies of Cu 2 Te.…”

“…39-1061), which is in good agreement with the previous reports. 25,26,31 The X-ray photoelectron spectroscopy (XPS) is applied to observe the surface chemical composition and elemental bonding configuration of obtained Cu 2 Te nanosheets. Figure 1e displays the Cu 2p and Te 3d binding energies of Cu 2 Te.…”

“…Wang et al reported a vertical growth of scalable 2D Cu 2 Te nanosheet arrays on copper foils by chemical etching and CVD for electrocatalytic CO 2 methanation . Yin et al prepared ultrathin Cu 2 Te nanosheets on mica by APCVD at a high temperature of about 800 °C and studied memristors and resistance switches using the transferred Cu 2 Te on SiO 2 /Si. , However, the former synthesis method of 2D Cu 2 Te requires ultrahigh vacuum or high temperature and a special substrate for in-depth exploration of 2D Cu 2 Te crystals and construction functional devices on SiO 2 /Si substrates are difficult. The studies on layer-controlled synthesis of a high-quality ultrathin Cu 2 Te single crystal on SiO 2 /Si and their optoelectrical properties have also rarely been reported.…”

van der Waals Epitaxial Growth of One-Unit-Cell-Thick Ferroelectric CuCrS2 Nanosheets

“…Figure b shows a schematic illustration of CVD growth of 2D CuCrS 2 nanosheets. The key to this process is utilizing freshly cleaved mica sheets, which have an atomically smooth and chemically inert surface, as the van der Waals epitaxial substrates . High-purity Cu, Cr, and S powders were used as the precursors.…”

“…The key to this process is utilizing freshly cleaved mica sheets, which have an atomically smooth and chemically inert surface, as the van der Waals epitaxial substrates. 18 High-purity Cu, Cr, and S powders were used as the precursors. In addition, the introduction of sodium chloride, which has been proven to decrease the reaction temperature, is essential for the epitaxial growth of nonlayered CuCrS 2 nanosheets.…”