Transparent Large-Area MoS₂ Phototransistors with Inkjet-Printed Components on Flexible Platforms

Abstract

Two-dimensional (2D) transition-metal dichalcogenides (TMDCs) have gained considerable attention as an emerging semiconductor due to their promising atomically thin film characteristics with good field-effect mobility and a tunable band gap energy. However, their electronic applications have been generally realized with conventional inorganic electrodes and dielectrics implemented using conventional photolithography or transferring processes that are not compatible with large-area and flexible device applications. To facilitate the advantages of 2D TMDCs in practical applications, strategies for realizing flexible and transparent 2D electronics using low-temperature, large-area, and low-cost processes should be developed. Motivated by this challenge, we report fully printed transparent chemical vapor deposition (CVD)-synthesized monolayer molybdenum disulfide (MoS) phototransistor arrays on flexible polymer substrates. All the electronic components, including dielectric and electrodes, were directly deposited with mechanically tolerable organic materials by inkjet-printing technology onto transferred monolayer MoS, and their annealing temperature of <180 °C allows the direct fabrication on commercial flexible substrates without additional assisted-structures. By integrating the soft organic components with ultrathin MoS, the fully printed MoS phototransistors exhibit excellent transparency and mechanically stable operation.

Gate‐Tunable Photoresponse Time in Black Phosphorus–MoS2 Heterojunctions

“…Therefore, the photoresponse time increases when the MoS 2 channel is in the off‐state since the carrier transit time is the key factor that limits the photoresponse time . Similar results have been reported in MoS 2 phototransistors, where a large decrease in the photoresponse time was observed when the MoS 2 channel was turned on . Moreover, photons with a shorter wavelength and thus higher energy can transfer more energy to EHPs, leading to high energy photoexcited electrons with a higher probability to overcome the Schottky barrier at the MoS 2 –metal interface and trapping states along the channel when the MoS 2 channel is in the off‐state .…”

“…Thus, there is no delay for the decay time under this circumstance. In our experiment, a decay time of 13 µs regardless of the incident laser wavelength has been achieved with a gate voltage of 20 V, which is several times faster than that of other BP–MoS 2 heterjunctions as well as BP and MoS 2 based phototransistors . Here, the rise and decay times are mainly limited by the sizable Schottky barrier at the MoS 2 –metal interface.…”

Fully Transparent p‐MoTe2 2D Transistors Using Ultrathin MoOx/Pt Contact Media for Indium‐Tin‐Oxide Source/Drain

“…As a potential application of display electronics, even transparent FET devices have been reported using 2D n‐type MoS 2 channel which was grown by chemical vapor deposition (CVD) method. However, such transparent 2D FETs are very few in report if devices with graphene gate and source/drain (S/D) contact are excluded, and moreover no transparent 2D‐like FETs with p‐type channel are seen, yet . In general, the mobilities of transparent 2D‐like FETs directly using conventional transparent conductor are not high enough because a good S/D ohmic contact might not be easy to form on the TMD channel.…”

Advanced Nanomaterials, Printing Processes, and Applications for Flexible Hybrid Electronics

“…Recently, transition metal dichalcogenides (TMDs), such as MoS, MoSe 2 , and Bi 2 Te 3 , have attracted attention due to their atomic thickness, high surface-to-volume ratio, and tunable bandgap. However, it is challenging to obtain monolayer TMDs films by a widely used method such as exfoliation, thinning, and liquid intercalation [87].…”