Strain-Gated Field Effect Transistor of a MoS₂–ZnO 2D–1D Hybrid Structure

Abstract

Two-dimensional (2D) molybdenum disulfide (MoS2) is an exciting material due to its unique electrical, optical, and piezoelectric properties. Owing to an intrinsic band gap of 1.2–1.9 eV, monolayer or a-few-layer MoS2 is used for fabricating field effect transistors (FETs) with high electron mobility and on/off ratio. However, the traditional FETs are controlled by an externally supplied gate voltage, which may not be sensitive enough to directly interface with a mechanical stimulus for applications in electronic skin. Here we report a type of top-pressure/force-gated field effect transistors (PGFETs) based on a hybrid structure of a 2D MoS2 flake and 1D ZnO nanowire (NW) array. Once an external pressure is applied, the piezoelectric polarization charges created at the tips of ZnO NWs grown on MoS2 act as a gate voltage to tune/control the source–drain transport property in MoS2. At a 6.25 MPa applied stimulus on a packaged device, the source–drain current can be tuned for ∼25%, equivalent to the results of applying an extra −5 V back gate voltage. Another type of PGFET with a dielectric layer (Al2O3) sandwiched between MoS2 and ZnO also shows consistent results. A theoretical model is proposed to interpret the received data. This study sets the foundation for applying the 2D material-based FETs in the field of artificial intelligence.

Enhanced photoresponsivity of the MoS2-GaN heterojunction diode via the piezo-phototronic effect

“…In recent years, the newly emerging piezotronic and piezo-phototronic devices can use externally applied strain to tune electrical transport and directly convert strain to a change in semiconductor conductance via the piezo-electric polarization charges. 25,26,[37][38][39][40] Next, we also demonstrated the piezophototronic-enhanced photocurrent for the as-fabricated MoS 2 and GaN heterojunction diode. Before illuminating the device, the output characteristics are depicted as a function of externally applied pressure (strain) in Figure 4a.…”

Au NPs@MoS2Sub-Micrometer Sphere-ZnO Nanorod Hybrid Structures for Efficient Photocatalytic Hydrogen Evolution with Excellent Stability

“…After the introduction of Au NPs to the MoS 2 spheres, the Raman intensity of MoS 2 is obviously enhanced, which further proves that the plasmonic effect plays an important role in enhancing the light absorption of MoS 2 . For the Au@MoS 2 ‐ZnO sample, additional ZnO Raman modes at 327 and 437 cm –1 are easily observed . Moreover, the incorporation of the ZnO nanorods alters the Raman modes of MoS 2 : the E 2g 1 Raman mode disappears, and the intensity of the A 1g Raman mode declines.…”

Reconfigurable systems for multifunctional electronics

“…The 2D conducting and semiconducting nanomaterials that are exploited in FETs demonstrate low power consumption due to a high carrier mobility. 43,44 Due to the good Schottky contact, the FETs with MoS 2 as transistor channels (Fig. 3a, top) are reported to have large on/off ratio and strain-tunable drain current, known as the piezoresistive effect.…”

“…3a, bottom), drain current or IV curve of FETs can be tuned by applied pressure, in a high sensitivity with potential applications for electronic skin. 44 The high sensitivity is c Experimental steps to obtain rippled MoS 2 with an AFM image shown at the bottom (left). Photoluminescence emission measurement from the flat (blue) and wrinkled (red) regions in the same MoS 2 flake shows a red shift in a wrinkled region, indicating a reduced band gap due to the local strain (right).…”