Scaling behavior of hysteresis in multilayer MoS2 field effect transistors

Li, Tao; Du, Gang; Zhang, Baoshun; Zeng, Zhongming

doi:10.1063/1.4894865

Cited by 88 publications

(85 citation statements)

References 26 publications

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“…However, the photo-excited holes in MoTe 2 get trapped mostly at the MoTe 2 -SiO 2 interface as well as at the defect states inside the MoTe 2 closer to its valence band, which are mostly immobile (reflected in poor mobility <1 cm and hence do not participate in conduction. [32][33][34][35] This also explains why it takes almost a day to come back to its initial value after the light is off (Fig. 3c).…”

Section: Discussionmentioning

confidence: 82%

Photo-tunable transfer characteristics in MoTe2–MoS2 vertical heterostructure

et al. 2017

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Fabrication of the out-of-plane atomically sharp p-n junction by stacking two dissimilar two-dimensional materials could lead to new and exciting physical phenomena. The control and tunability of the interlayer carrier transport in these p-n junctions have a potential to exhibit new kind of electronic and optoelectronic devices. In this article, we present the fabrication, electrical, and optoelectrical characterization of vertically stacked few-layers MoTe 2 (p)-single-layer MoS 2 (n) heterojunction. Over and above the antiambipolar transfer characteristics observed similar to other hetero p-n junction, our experiments reveal a unique feature as a dip in transconductance near the maximum. We further observe that the modulation of the dip in the transconductance depends on the doping concentration of the two-dimensional flakes and also on the power density of the incident light. We also demonstrate high photo-responsivity of~10 5 A/W at room temperature for a forward bias of 1.5 V. We explain these new findings based on interlayer recombination rate-dependent semi-classical transport model. We further develop first principles-based atomistic model to explore the charge carrier transport through MoTe 2 -MoS 2 heterojunction. The similar dip is also observed in the transmission spectrum when calculated using density functional theory-non-equilibrium Green's function formalism. Our findings may pave the way for better understanding of atomically thin interface physics and device applications.

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Section: Discussionmentioning

confidence: 82%

Photo-tunable transfer characteristics in MoTe2–MoS2 vertical heterostructure

et al. 2017

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“…For large negative gate bias these trapped electrons are released from adsorbed molecules into the MoS 2 channel which reduces V TH . 19 This leads to a positive ΔV TH and therefore, clockwise hysteresis. However, our results do not support adsorbate mediated hysteresis because, (1) for measurements done in a dry vacuum/ nitrogen ambiance increasing the temperature should reduce the amount of absorbates on MoS 2 , and hence decrease the hysteresis until it collapses (shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…3 and Table 1) considered in previous studies. [16][17][18][19]22,23,25 Adsorbate mediated hysteresis mechanism 18,19 is shown in Fig. 3a.…”

Section: Resultsmentioning

confidence: 99%

“…15 Comparison of previous reports on hysteresis in MoS 2 devices with this work is listed in Table 1. Hysteresis observed in previous studies [16][17][18] has been attributed to several possibilities such as adsorption of water molecules, [18][19][20][21] oxide traps close to MoS 2 , 22 oxide-MoS 2 interface traps 23,24 and gate voltage stress effects. 25 A lack of uniformity in the hysteresis data and consensus on its origin among the reports listed in Table 1 results, at least partly, from differences in measurement conditions as well as device architecture.…”

Section: Introductionmentioning

confidence: 98%

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Reversible hysteresis inversion in MoS2 field effect transistors

et al. 2017

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The origin of threshold voltage instability with gate voltage in MoS 2 transistors is poorly understood but critical for device reliability and performance. Reversibility of the temperature dependence of hysteresis and its inversion with temperature in MoS 2 transistors has not been demonstrated. In this work, we delineate two independent mechanisms responsible for thermally assisted hysteresis inversion in gate transfer characteristics of contact resistance-independent multilayer MoS 2 transistors. Variable temperature hysteresis measurements were performed on gated four-terminal van der Pauw and two-terminal devices of MoS 2 on SiO 2 . Additional hysteresis measurements on suspended (~100 nm air gap between MoS 2 and SiO 2 ) transistors and under different ambient conditions (vacuum/nitrogen) were used to further isolate the mechanisms. Clockwise hysteresis at room temperature (300 K) that decreases with increasing temperature is shown to result from intrinsic defects/traps in MoS 2 . At higher temperatures a second, independent mechanism of charge trapping and de-trapping between the oxide and p + Si gate leads to hysteresis collapse at~350 K and anti-clockwise hysteresis (inversion) for temperatures >350 K. The intrinsic-oxide trap model has been corroborated through device simulations. Further, pulsed current-voltage (I-V) measurements were carried out to extract the trap time constants at different temperatures. Non-volatile memory and temperature sensor applications exploiting temperature dependent hysteresis inversion and its reversibility in MoS 2 transistors have also been demonstrated. npj 2D Materials and Applications (2017) 1:34 ; doi:10.1038/s41699-017-0038-y INTRODUCTION Among two-dimensional materials, graphene 1,2 was the first to be isolated and studied with respect to electronic applications. Due to lack of an energy bandgap in graphene, other 2D materials such as layered transition metal dichalcogenides (TMDs) comprising a wide selection of materials with different bandstructures, and therefore different electrical and optical properties, have garnered significant attention.3-5 Molybdenum disulfide (MoS 2 ) has emerged as a prospective candidate for transistor applications. The presence of a direct bandgap (~1.8 eV) in monolayer form and an indirect bandgap (~1.2 eV) in multilayer MoS 2 makes it a promising channel material for field effect transistors (FETs).

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“…In our previous report, we showed that the hysteresis was exponentially proportional to the range of V bg . 22 The field-effect mobility (µ FE ) of MoS 2 FETs increased significantly when high-κ Al 2 O 3 replaced SiO 2 as the back-gate dielectrics (Fig. 2(d)).…”

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confidence: 99%

Electrical performance of multilayer MoS2 transistors on high-κ Al2O3 coated Si substrates

Wan

et al. 2015

AIP Advances

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The electrical performance of MoS2 can be engineered by introducing high-κ dielectrics, while the interactions between high-κ dielectrics and MoS2 need to be studied. In this study, multilayer MoS2 field-effect transistors (FETs) with a back-gated configuration were fabricated on high-κ Al2O3 coated Si substrates. Compared with MoS2 FETs on SiO2, the field-effect mobility (μFE) and subthreshold swing (SS) were remarkably improved in MoS2/Al2O3/Si. The improved μFE was thought to result from the dielectric screening effect from high-κ Al2O3. When a HfO2 passivation layer was introduced on the top of MoS2/Al2O3/Si, the field-effect mobility was further enhanced, which was thought to be concerned with the decreased contact resistance between the metal and MoS2. Meanwhile, the interface trap density increased from 2.4×1012 eV−1cm−2 to 6.3×1012 eV−1cm−2. The increase of the off-state current and the negative shift of the threshold voltage may be related to the increase of interface traps.

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Scaling behavior of hysteresis in multilayer MoS2 field effect transistors

Cited by 88 publications

References 26 publications

Photo-tunable transfer characteristics in MoTe2–MoS2 vertical heterostructure

Photo-tunable transfer characteristics in MoTe2–MoS2 vertical heterostructure

Reversible hysteresis inversion in MoS2 field effect transistors

Electrical performance of multilayer MoS2 transistors on high-κ Al2O3 coated Si substrates

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