High-performance multilayer WSe2 field-effect transistors with carrier type control

Pudasaini, Pushpa Raj; Oyedele, Akinola D.; Zhang, Cheng; Stanford, Michael G.; Cross, Nicholas; Wong, Anthony T.; Hoffman, Anna N.; Xiao, Kai; Duscher, Gerd; Mandrus, David; Ward, Thomas Z.; Rack, Philip D.

doi:10.1007/s12274-017-1681-5

Cited by 115 publications

(107 citation statements)

References 42 publications

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“…Such reference device featured poor electrical properties (dashed line in Fig.1c and d), with very low drain source current (I < 1 nA in the entire gate-voltage range explored in this study), corresponding to an electron mobility on the order of 10 -6 cm 2 V -1 s -1 . Such poor performances, which are comparable to those reported for single-layer WSe2 on SiO2 substrates with Au electrodes, 21,22 are caused by the almost-blocked charge injection from Au into WSe2, which introduces ultra-high contact resistance. When exfoliated and placed on top of the PFS SAM, WSe2 based transistors displayed improved charge transport, with higher current balanced ambipolarity but still relatively low hole and electron mobilities (µh ~ µe ~ 0.5 cm 2 V -1 s -1 ).…”

Section: Figures 1 C and D Show The Device Architecture And Transfer supporting

confidence: 61%

Boosting and Balancing Electron and Hole Mobility in Single- and Bilayer WSe₂ Devices via Tailored Molecular Functionalization

et al. 2019

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WSe2 is a layered ambipolar semiconductor enabling hole and electron transport, which renders it a suitable active component for logic circuitry. However, solid-state devices based on singleand bi-layer WSe2 typically exhibit unipolar transport and poor electrical performances when conventional SiO2 dielectric and Au electrodes are used. Here, we show that silane-containing functional molecules form ordered monolayers on the top of the WSe2 surface, thereby boosting its electrical performance in single-and bi-layer field-effect transistors. In particular, by employing SiO2 dielectric substrates and top Au electrodes, we measure unipolar mobility as high as µh = 150 cm 2 V-1 s-1 and µe = 17.9 cm 2 V-1 s-1 in WSe2 single-layer devices when ad hoc molecular monolayers are chosen. Additionally, by asymmetric double-side functionalization with two different molecules, we provide opposite polarity to the top and bottom layer of bi-layer WSe2, demonstrating nearly balanced ambipolarity at the bi-layer limit. Our results indicate that the controlled functionalization of the two sides of WSe2 mono-and bilayer flakes with highly ordered molecular monolayers offers the possibility to simultaneously achieve energy level engineering and defect functionalization, representing a path towards the deterministic control over charge transport in 2D materials.

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Section: Figures 1 C and D Show The Device Architecture And Transfer supporting

confidence: 61%

Boosting and Balancing Electron and Hole Mobility in Single- and Bilayer WSe₂ Devices via Tailored Molecular Functionalization

et al. 2019

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“…Alternately, the metal contact is also another critical role in transport. Pudasaini et al 34 reported that the carrier type can evolve from ptype to ambipolar to n-type in WSe 2 using Cr (the work function of Cr is 4.6 eV) contact with increasing channel thickness. In thinner WSe 2 , the hole conduction appears dominant because the aligned Fermi level of thinner WSe 2 /Cr contact is below the middle of the bandgap.…”

Section: Resultsmentioning

confidence: 99%

The ambipolar transport behavior of WSe2 transistors and its analogue circuits

et al. 2018

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Tungsten diselenide (WSe 2 ) has many excellent properties and provides superb potential in applications of valleybased electronics, spin-electronics, and optoelectronics. To facilitate the digital and analog application of WSe 2 in CMOS, it is essential to understand the underlying ambipolar hole and electron transport behavior. Herein, the electric field screening of WSe 2 with a thickness range of 1-40 layers is systemically studied by electrostatic force microscopy in combination with non-linear Thomas-Fermi theory to interpret the experimental results. The ambipolar transport behavior of 1-40 layers of WSe 2 transistors is systematically investigated with varied temperature from 300 to 5 K. The thickness-dependent transport properties (carrier mobility and Schottky barrier) are discussed. Furthermore, the surface potential of WSe 2 as a function of gate voltage is performed under Kelvin probe force microscopy to directly investigate its ambipolar behavior. The results show that the Fermi level will upshift by 100 meV when WSe 2 transmits from an insulator to an n-type semiconductor and downshift by 340 meV when WSe 2 transmits from an insulator to a p-type semiconductor. Finally, the ambipolar WSe 2 transistor-based analog circuit exhibits phase-control by gate voltage in an analog inverter, which demonstrates practical application in 2D communication electronics.

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“…Third, the monolayer 2D materials are extremely sensitive to the change of environment because all atoms are exposed on the surface. In other words, the electronic and photoelectric devices based on 2D layered materials can be facilely modulated by various methods (e.g., surface treatment, chemical doping, physical process, interface, and electrode contacts). Based on the two properties of 2D layered materials described above (layer‐dependent bandgap and sensitivity to the environment), 2D layered materials may possess different ambipolar mechanisms compared with previously mentioned organic semiconductors.…”

Section: Inorganic Semiconducting Materialsmentioning

confidence: 99%

“…In addition, the ambipolar characteristic can also be controlled by operation temperature, ferroelectric top gate dielectric (poly(vinylidenefluoride‐ co ‐trifluoroethylene) (P(VDF‐TrFE))) as well as channel thickness of WSe 2 . Recently, Pudasaini et al achieved controllable charge type in FETs on the basis of WSe 2 semiconducting channel and Cr/Au contacts via tuning the thickness of semiconducting channel and exploiting remote oxygen plasma surface treatment . By changing the thickness of semiconducting channel, the transport performance of WSe 2 transistors could evolve from n‐type (more than 5 nm) to ambipolar (about 4 nm) or p‐type (less than 3 nm), which originated from the changeable energy gaps of WSe 2 as well as carrier band offsets.…”

Section: Inorganic Semiconducting Materialsmentioning

confidence: 99%

Recent Advances in Ambipolar Transistors for Functional Applications

Ren

Yang

Zhou

et al. 2019

Adv Funct Materials

182

139

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Ambipolar transistors represent a class of transistors where positive (holes) and negative (electrons) charge carriers both can transport concurrently within the semiconducting channel. The basic switching states of ambipolar transistors are comprised of common off-state and separated on-state mainly impelled by holes or electrons. During the past years, diverse materials are synthesized and utilized for implementing ambipolar charge transport and their further emerging applications comprising ambipolar memory, synaptic, logic, and light-emitting transistors on account of their special bidirectional carrier-transporting characteristic. Within this review, recent developments of ambipolar transistor field involving fundamental principles, interface modifications, selected semiconducting material systems, device structures, ambipolar characteristics, and promising applications are highlighted. The existed challenges and prospective for researching ambipolar transistors in electronics and optoelectronics are also discussed. It is expected that the review and outlook are well timed and instrumental for the rapid progress of academic sector of ambipolar transistors in lighting, display, memory, as well as neuromorphic computing for artificial intelligence.

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High-performance multilayer WSe2 field-effect transistors with carrier type control

Cited by 115 publications

References 42 publications

Boosting and Balancing Electron and Hole Mobility in Single- and Bilayer WSe₂ Devices via Tailored Molecular Functionalization

Boosting and Balancing Electron and Hole Mobility in Single- and Bilayer WSe₂ Devices via Tailored Molecular Functionalization

The ambipolar transport behavior of WSe2 transistors and its analogue circuits

Recent Advances in Ambipolar Transistors for Functional Applications

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High-performance multilayer WSe2 field-effect transistors with carrier type control

Cited by 115 publications

References 42 publications

Boosting and Balancing Electron and Hole Mobility in Single- and Bilayer WSe2 Devices via Tailored Molecular Functionalization

Boosting and Balancing Electron and Hole Mobility in Single- and Bilayer WSe2 Devices via Tailored Molecular Functionalization

The ambipolar transport behavior of WSe2 transistors and its analogue circuits

Recent Advances in Ambipolar Transistors for Functional Applications

Contact Info

Product

Resources

About

Boosting and Balancing Electron and Hole Mobility in Single- and Bilayer WSe₂ Devices via Tailored Molecular Functionalization

Boosting and Balancing Electron and Hole Mobility in Single- and Bilayer WSe₂ Devices via Tailored Molecular Functionalization