Abstract: Provided is a method for synthesizing 2H/1T? transition metal dichalcogenide (TMD) heterophase junctions. Synthesis of vertical 2H/1T? MoS2 heterophase junction is achieved by growing 2H MoS2 monolayers on a mica substrate under pure Ar carrier gas, and then growing 1T? MoS2 nanoribbons on top of the 2H MoS2 monolayers by changing the carrier gas from pure Ar to a mixture of Ar and H2 gases. The integrated devices based on 2H/1T? MoS2 heterophase structures display typical rectifying behavior with a current rectifying ratio of over 102 and achieve a responsivity of 1.07 A/W at 532 nm with an ultra-low dark current of lower than 10-11 A. These superior features make 2H/1T? MoS2 heterophase structure a promising candidate for future rectifiers as well as photodetectors. More importantly, the provided synthesis method can pave the way toward tailoring the phase in MoS2 to promote the performance of electronic devices.

Abstract: Provided is a method for synthesizing 2H/1T? transition metal dichalcogenide (TMD) heterophase junctions. Synthesis of vertical 2H/1T? MoS2 heterophase junction is achieved by growing 2H MoS2 monolayers on a mica substrate under pure Ar carrier gas, and then growing 1T? MoS2 nanoribbons on top of the 2H MoS2 monolayers by changing the carrier gas from pure Ar to a mixture of Ar and H2 gases. The integrated devices based on 2H/1T? MoS2 heterophase structures display typical rectifying behavior with a current rectifying ratio of over 102 and achieve a responsivity of 1.07 A/W at 532 nm with an ultra-low dark current of lower than 10?11 A. These superior features make 2H/1T? MoS2 heterophase structure a promising candidate for future rectifiers as well as photodetectors. More importantly, the provided synthesis method can pave the way toward tailoring the phase in MoS2 to promote the performance of electronic devices.

Abstract: The present invention provides a general salt-assisted chemical vapour deposition method for phase-controllable synthesis of 1T? and 2H-phase transition metal dichalcogenide (TMD) monolayer crystals. The method comprises: mixing a transition metal compound powder and a salt powder to form a precursor; placing a substrate on top of the precursor; placing the precursor and the substrate at a center position in a chemical vapour deposition (CVD) furnace; placing a chalcogen powder at an upstream position relative to the precursor along a gas-flow direction in the CVD furnace; heating up the CVD furnace to a growth temperature within the heat-up time; keeping the CVD furnace at the growth temperature for a growth time under a mixed gas flow of H2 and Ar. The optical and electrical characterizations reveal the phase-dependent in-plane isotropy and anisotropy of the as-synthesized 2H and 1T?-phase crystals. The 1T?-TMD monolayer crystals demonstrate much-improved phase transition temperatures.

Abstract: Respiratory System Similation Systems that mimic human or other animal exhalation events are disclosed. Exhalation events that can be reproduced include coughing, sneezing, breathing, talking, gagging, panting, and singing. Air flow and airway systems cooperate to eject a gas cloud comprising the at least some air produced from the air flow system and one or more of a plurality of droplets, solid residues, or aerosols. The exhalation emission systems can be used in testing emissions in various environments, medical, and protective equipment usage situations. Methods related to the same are also disclosed.