Bulk transport and contact limitation of MoS₂ multilayer flake transistors untangled via temperature-dependent transport measurements

Abstract

Rational use of novel high‐performance semiconductors in field‐effect transistors (FETs) requires exact knowledge of the dominating charge transport mechanisms. In particular, the distinction between contact‐ and semiconductor‐limited transport is important in FETs with small channel lengths. Here, we analyze the relative contributions of contact limitation and intrinsic conductivity of FETs based on mechanically exfoliated multilayers of the high performance n‐type semiconductor molybdenum disulfide (MoS2). Based on a lithography‐free fabrication process, we realize FETs with room temperature mobility (μ) of up to 46.8 cm2/Vs and ION/IOFF ratio of up to 105. Using temperature‐ and bias‐dependent charge transport measurements, we are able to show that the intrinsic bulk transport in the flake can be best described by a phonon‐limited band transport model with a conductive bulk at room temperature that freezes out upon cooling of the sample. In addition, we notice an increase of μ by a factor of 2–5 when using a self‐assembled monolayer (SAM)‐modified SiO2/MoS2 interface. More importantly, we show that the choice of drain–source bias (VDS) is crucial when interpreting MoS2 transport measurements, while for large VDS the intrinsic semiconductor transport properties can be observed, a strong contact limitation appears at low VDS. Our combined measurements allow us to distinguish between the effect of bulk and semiconductor/dielectric interface transport and the effect of contact resistance on the electrical transport properties.

Covalently interconnected transition metal dichalcogenide networks via defect engineering for high-performance electronic devices

“…As for LG-TFTs (Fig. 3), the superior electrical performance of MoS2 networks arise when the Schottky barrier is attenuated by the application of a VG 46 . Fig.…”

Oriented Thiophene‐Extended Benzotrithiophene Covalent Organic Framework Thin Films: Directional Electrical Conductivity

“…[ 24 ] The temperature‐dependent conductivity values presented in Figure 4a are therefore determined at drain‐source voltage ( V DS ) = 40 V, since the influence of the contact resistance is less pronounced at such high voltages. [ 25 ] At room temperature, this results in a conductivity of ≈8.7 × 10 –4 S m −1 for of BTT TTA and ≈1.1 × 10 –4 S m −1 for BTT TTTBA, which places them among the most conductive non‐doped COFs reported to date. [ 26 ] Notably, in‐plane conductivity measurements of films of different thicknesses (320, 380, and 590 nm in the case of BTT TTA and 290, 430, and 480 nm in the case of BTT TTTBA) show similar conductivity values.…”

Manipulating nanoscale structure to control functionality in printed organic photovoltaic, transistor and bioelectronic devices

“…OTFTs can be further categorised according to the mechanism by which current flowing between their source and drain electrodes is modulated; common categories include OFETs, electrolyte-gated organic field effect transistors (EGOFETs), water-gated organic field-effect transistors (WGOFETs) and organic electrochemical transistors (OECTs). Indeed, the research laboratories of several multinational technology companies have been publishing the results of their research and development of the field at various times over the last two decades [210][211][212]. However, in this arena we note that the implementation of R2R fabrication for OTFTs has not yet been realised to the same extent as with OPV devices [213].…”