Large‐Area Monolayer MoS<sub>2</sub> for Flexible Low‐Power RF Nanoelectronics in the GHz Regime

Chang, Hui-Ming; Yogeesh, Maruthi N.; Ghosh, Rohit; Rai, Amritesh; Sanne, Atresh; Yang, Shixuan; Lu, Nanshu; Banerjee, Sanjay K.; Akinwande, Deji

doi:10.1002/adma.201504309

Cited by 166 publications

(149 citation statements)

References 37 publications

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“…The electrostatic control is improved over top-gated devices because the electric field flux reaching the MoS 2 channel is increased at an equivalent gate voltage. As an enhancement mode device, we can sufficiently deplete the channel to achieve an I ON /I OFF ratio of 10 8 . Figure 2c shows the I ds −V ds output characteristics for the same device.…”

Section: Resultsmentioning

confidence: 99%

“…6 However, for industrial scale applications, the mechanical cleavage process is not scalable and, thus far, there have been few studies on chemical vapor deposited (CVD) MoS 2 RF FETs. 7,8 Our prior results demonstrated monolayer CVD MoS 2 top-gated FETs with an f T of 6.2 GHz. 7 Furthermore, the work of Chang et al used transferred monolayer CVD MoS 2 on a flexible substrate to achieve an f T of 5.6 GHz.…”

Section: Molybdenum Disulfide (Mosmentioning

confidence: 99%

“…7 Furthermore, the work of Chang et al used transferred monolayer CVD MoS 2 on a flexible substrate to achieve an f T of 5.6 GHz. 8 As has been done with exfoliated MoS 2 , optimized device configurations must be applied to CVD MoS 2 to push cut off frequencies higher. In this study, we take a step in this direction by taking an embedded gate approach to CVD MoS 2 FETs.…”

Section: Molybdenum Disulfide (Mosmentioning

confidence: 99%

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Embedded gate CVD MoS2 microwave FETs

et al. 2017

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Recent studies have increased the cut off frequencies achievable by exfoliated MoS 2 by employing a combination of channel length scaling and geometry modification. However, for industrial scale applications, the mechanical cleavage process is not scalable but, thus far, the same device improvements have not been realized on chemical vapor deposited MoS 2 . Here we use a gate-first process flow with an embedded gate geometry to fabricate short channel chemical vapor deposited MoS 2 radio frequency transistors with a notable f T of 20 GHz and f max of 11.4 GHz, and the largest high-field saturation velocity, v sat = 1.88 × 10 6 cm/s, in MoS 2 reported so far. The gate-first approach, facilitated by cm-scale chemical vapor deposited MoS 2 , offers enhancement mode operation, I ON /I OFF ratio of 10 8 , and a transconductance (g m ) of 70 μS/μm. The intrinsic f T (f max ) obtained here is 3X (2X) greater than previously reported top-gated chemical vapor deposited MoS 2 radio frequency field-effect transistors. With as-measured S-parameters, we demonstrate the design of a GHz MoS 2 -based radio frequency amplifier. This amplifier has gain greater then 15 dB at 1.2 GHz, input return loss > 10 dB, bandwidth > 200 MHz, and DC power consumption of~10 mW.

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Section: Resultsmentioning

confidence: 99%

Section: Molybdenum Disulfide (Mosmentioning

confidence: 99%

Section: Molybdenum Disulfide (Mosmentioning

confidence: 99%

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Embedded gate CVD MoS2 microwave FETs

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“…19 The evolution of the carrier density distribution in the MoS2 channel as a function of the bias and the formation of depletion regions is shown for all devices in short-channel back-gated MoS2 FETs (L = 500 nm) that showed two orders of magnitude higher current density due to higher mobility (~50 cm 2 /Vs). 24,25 The ultimate scaling of these MoS2 transistors to L = 50 nm further increased the current density (>50 μA/μm), but no current saturation was observed due to severe short-channel effects. 11 The self-alignment approach also facilitates the reliable fabrication of p-n vdWHs with small footprints and unique electrostatic gating control.…”

Section: Toc Imagementioning

confidence: 99%

“…2g) short-channel back-gated MoS2 FETs (L = 500 nm) that showed two orders of magnitude higher current density due to higher mobility (~50 cm 2 /Vs). 24,25 The ultimate scaling of these MoS2 transistors to L = 50 nm further increased the current density (>50 μA/μm), but no current saturation was observed due to severe short-channel effects. 11…”

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confidence: 99%

Self-Aligned van der Waals Heterojunction Diodes and Transistors

et al. 2018

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A general self-aligned fabrication scheme is reported here for a diverse class of electronic devices based on van der Waals materials and heterojunctions. In particular, self-alignment enables the fabrication of source-gated transistors in monolayer MoS2 with near-ideal current saturation characteristics and channel lengths down to 135 nm. Furthermore, self-alignment of van der Waals p-n heterojunction diodes achieves complete electrostatic control of both the p-type and n-type constituent semiconductors in a dual-gated geometry, resulting in gate-tunable mean and variance of anti-ambipolar Gaussian characteristics. Through finite-element device simulations, the operating principles of source-gated transistors and dual-gated anti-ambipolar devices are elucidated, thus providing design rules for additional devices that employ self-aligned geometries. 2For example, the versatility of this scheme is demonstrated via contact-doped MoS2 homojunction diodes and mixed-dimensional heterojunctions based on organic semiconductors. The scalability of this approach is also shown by fabricating self-aligned short-channel transistors with subdiffraction channel lengths in the range of 150 nm to 800 nm using photolithography on large-area MoS2 films grown by chemical vapor deposition. Overall, this self-aligned fabrication method represents an important step towards the scalable integration of van der Waals heterojunction devices into more sophisticated circuits and systems. TOC IMAGE 3Parallel self-aligned fabrication methods in modern silicon-based microelectronics have enabled sub-lithographic registration between processing steps, ultimately facilitating substantial advances in circuit complexity over the past few decades. 1 In contrast, while two-dimensional (2D) materials have shown significant potential for digital and analog electronics due to their high mobilities, ultrathin geometry, and broad range of permutations in van der Waals heterojunctions (vdWHs), 2-9 2D material devices have not yet exploited parallel self-aligned fabrication to achieve both short channels and large area fabrication. Thus far, short-channel 2D material transistors and vdWHs have been achieved using serial processing methods such as electron-beam lithography or mechanical placement on nanotube or nanowire gates. 5,10,11 Similarly, the relative alignment of different layers in vdWHs has been inhibited by the diffraction-limited resolution of transfer and alignment methods. Here, we overcome these limitations by introducing a self-aligned processing methodology that enables the fabrication of 2D material transistors with channel lengths below 150 nm with minimal short-channel effects and improved current saturation, as demonstrated with monolayer MoS2. These self-aligned transistors show the highest output resistance at the lowest channel length reported for a 2D material, which is of interest for high-frequency current amplifiers and mixers. In vdWHs based on black phosphorus (BP) and MoS2, this self-aligned approach allows dual-gate ...

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High‐Performance Flexible Multilayer MoS₂ Transistors on Solution‐Based Polyimide Substrates

Song

Kwon

Park

et al. 2016

Adv Funct Materials

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Transition metal dichalcogenides (TMDs) layers of molecular thickness, in particular molybdenum disulfide (MoS2), become increasingly important as active elements for mechanically flexible/stretchable electronics owing to their relatively high carrier mobility, wide bandgap, and mechanical flexibility. Although the superior electronic properties of TMD transistors are usually integrated into rigid silicon wafers or glass substrates, the achievement of similar device performance on flexible substrates remains quite a challenge. The present work successfully addresses this challenge by a novel process architecture consisting of a solution‐based polyimide (PI) flexible substrate in which laser‐welded silver nanowires are embedded, a hybrid organic/inorganic gate insulator, and multilayers of MoS2. Transistors fabricated according to this process scheme have decent properties: a field‐effect‐mobility as high as 141 cm2 V−1 s−1 and an Ion/Ioff ratio as high as 5 × 105. Furthermore, no apparent degradation in the device properties is observed under systematic cyclic bending tests with bending radii of 10 and 5 mm. Overall electrical and mechanical results provide potentially important applications in the fabrication of versatile areas of flexible integrated circuitry.

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Large‐Area Monolayer MoS₂ for Flexible Low‐Power RF Nanoelectronics in the GHz Regime

Abstract: Flexible synthesized MoS2 transistors are advanced to perform at GHz speeds. An intrinsic cutoff frequency of 5.6 GHz is achieved and analog circuits are realized. Devices are mechanically robust for 10,000 bending cycles.

Cited by 166 publications

References 37 publications

Embedded gate CVD MoS2 microwave FETs

Embedded gate CVD MoS2 microwave FETs

Self-Aligned van der Waals Heterojunction Diodes and Transistors

High‐Performance Flexible Multilayer MoS₂ Transistors on Solution‐Based Polyimide Substrates

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Large‐Area Monolayer MoS2 for Flexible Low‐Power RF Nanoelectronics in the GHz Regime

Abstract: Flexible synthesized MoS2 transistors are advanced to perform at GHz speeds. An intrinsic cutoff frequency of 5.6 GHz is achieved and analog circuits are realized. Devices are mechanically robust for 10,000 bending cycles.

Cited by 166 publications

References 37 publications

Embedded gate CVD MoS2 microwave FETs

Embedded gate CVD MoS2 microwave FETs

Self-Aligned van der Waals Heterojunction Diodes and Transistors

High‐Performance Flexible Multilayer MoS2 Transistors on Solution‐Based Polyimide Substrates

Contact Info

Product

Resources

About

Large‐Area Monolayer MoS₂ for Flexible Low‐Power RF Nanoelectronics in the GHz Regime

High‐Performance Flexible Multilayer MoS₂ Transistors on Solution‐Based Polyimide Substrates