Polyvinylalcohol (PVA)-Assisted Exfoliation of ReS Nanosheets and the Use of ReS-PVA Composites for Transparent Memristive Photosynapse Devices.

Two-dimensional (2D) transition metal dichalcogenides (TMDs) have attracted significant attention for their outstanding optoelectrical properties. Unlike most TMDs with layer-dependent photoresponsivity, rhenium disulfide (ReS) shows excellent thickness-independent photoresponsivity. Herein, we show a surfactant-free polyvinyl alcohol (PVA)-assisted exfoliation method for 2D-TMDs in aqueous solution and a transparent photosensitive memristor synapse device based on ReS nanosheets composited with PVA.

Photo-Carrier-Guiding Behavior of Vertically Grown MoS and MoSe in Highly Efficient Low-Light Transparent Photovoltaic Devices on Large-Area Rough Substrates.

Two-dimensional MoX (X = S, Se) films were vertically grown on highly rough transparent conducting F-doped SnO glass substrates for the first time and successfully used as photogenerated carrier-guiding layers (CGLs) in transparent hydrogenated amorphous silicon (a-Si:H) thin film solar cells (TFSCs). The MoSe CGL layers could be grown at 530 °C using thermally cracked small Se-molecules on transparent FTO glass substrates and significantly improved cell performance. A transparent cell transmitting 26.

Metal-agglomeration-suppressed growth of MoS and MoSe films with small sulfur and selenium molecules for high mobility field effect transistor applications.

This work reports a breakthrough technique for achieving high quality and uniform molybdenum dichalcogenide (MoX2 where X = S, Se) films on large-area wafers via metal-agglomeration-suppressed growth (MASG) with small chalcogen (X-) molecules at growth temperatures (TG) of 600 °C or lower. In order to grow MoS2 films suitable for field effect transistors (FETs), S-molecules should be pre-deposited on Mo films at 60 °C prior to heating the substrate up to TG. The pre-deposited S-molecules successfully suppressed the agglomeration of Mo during sulfurization and prevented the formation of protruding islands in the resultant sulfide films.

Visible Light-Erasable Oxide FET-Based Nonvolatile Memory Operated with a Deep Trap Interface.

A new concept of a tunneling oxide-free nonvolatile memory device with a deep trap interface floating gate is proposed. This device demonstrates a high on/off current ratio of 10 and a sizable memory window due to deep traps at the interface between the channel and gate dielectric layers. Interestingly, irradiation with 400 nm light can completely restore the program state to the initial one (performing an erasing process), which is attributed to the visible light-sensitive channel layer.