Abstract
Transition metal dichalcogenides (TMDCs), such as MoS2 and WSe2, provide two-dimensional atomic crystals with semiconductor band gap. In this work, we present a design of new mechano-electric generators and sensors based on transition metal dichalcogenide nanoribbon PN junctions and heterojunctions. The mechano-electric conversion was simulated by using a first-principle calculation. The output voltage of MoS2 nanoribbon PN junction increases with strain, reaching 0.036 V at 1% strain and 0.31 V at 8% strain, much larger than the reported results. Our study indicates that the length, width and layer number of TMDC nanoribbon PN junctions have an interesting but different impact on the voltage output. Also, the results indicate that doping position and concentration only cause a small fluctuation in the output voltage. These results have been compared with the mechano-electric conversion of TMDC heterojunctions. Such novel mechano-electric generators and sensors are very attractive for applications in future self-powered, wearable electronics and systems.
Highlights
Enlightened by the intrinsic piezoelectricity of TMDCs based two dimensional monolayer, we have designed and simulated a novel piezoelectric device realized by MoS2 monolayer based PN junction
Its electromechanical property was simulated by first-principle calculations. 0.31 V of output voltage can be achieved by 0.051 eV/ Å 3 of the laterally tensile stress, which leads to 8% strain in transport direction
We have demonstrated the time domain-output voltage in the case of the applied stress in Sine waveform
Summary
The energy diagrams of 2D TMDC nanoribbon PN junctions and heterojunctions have been calculated by first principle calculations carried out by the density functional theory (DFT) in Virtual Nanolab ATK package[28]. The maximum number of fully self-consistent field (SCF) iteration steps was set to 100029. The self-consistent field calculations were checked strictly to guarantee fully converging within the iteration steps. In order to clearly illustrate the design and characteristics of TMDC junction mechano-electric converters, the results are reported as follows: (1) The intrinsic piezoelectricity of 2D infinite MoS2 monolayer was studied. (2) The PN junction-based device electric output performance was evaluated. (4) The fluctuation in output voltage induced by various doping positions and concentrations was studied. (5) The mechano-electric conversion of TMDC nanoribbon heterojunctions were studied and compared with In order to clearly illustrate the design and characteristics of TMDC junction mechano-electric converters, the results are reported as follows: (1) The intrinsic piezoelectricity of 2D infinite MoS2 monolayer was studied. (2) The PN junction-based device electric output performance was evaluated. (3) Effects of sizes (width, length and layer number) on output voltages were investigated. (4) The fluctuation in output voltage induced by various doping positions and concentrations was studied. (5) The mechano-electric conversion of TMDC nanoribbon heterojunctions were studied and compared with
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