2022 User Research Highlights
Wafer scalable single-layer amorphous MoO3

Project Summary: Molybdenum trioxide (a-MoO3) is a wide bandgap 2D layered oxide (Eg~3 eV) that is of interest for resistive switching-based nonvolatile memory devices.  It is difficult to produce large-area monolayer MoO3 through exfoliation of bulk crystals or other techniques. This study demonstrates a facile route to obtain wafer-scale monolayer amorphous MoO3 using monolayer 2D MoS2 grown by metalorganic chemical vapor deposition (MOCVD) as a starting material, following by UV-ozone oxidate at substrate temperatures as low as 120oC. The process yields smooth, continuous, uniform and stable monolayer oxide with wafer-scale homogeneity. Using the subnanometer MoO3 as the active layer sandwiched between two metal electrodes, we demonstrate the thinnest oxide-based nonvolatile resistive switching memory with low voltage operation and high ON/OFF ratio. These results, which are potentially extendable to other transition metal oxides, will enable further exploration of subnanometer stoichiometric MoO3, extending the frontiers of ultrathin flexible oxide materials and devices. Published in ACS Nano (2022), available online at: https://doi.org/10.1021/acsnano.1c07705

2DCC Role: The wafer-scale monolayer MoS2 used as the starting material in this study was produced by MOCVD in the 2DCC-MIP facility.