Ambipolar transport in CVD grown MoSe2 monolayer using an ionic liquid gel gate dielectric

Ortiz, Deliris; Ramos, Idalia; Pinto, Nicholas J.; Zhao, Meng‐Qiang; Kumar, Vinayak; Johnson, A. T. Charlie

doi:10.1063/1.5020443

Cited by 15 publications

(14 citation statements)

References 23 publications

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“…Our AlO x -capped 2L devices achieve a record-high current density for atomically thin MoSe 2 of ∼65 μA/μm, with an I on / I off > 10 6 and R C of ∼60 kΩ·μm. 30 , 34 , 38 − 40 These results represent ∼20× improvement in R C and ∼30× enhanced current density compared to our (AlO x -capped) 1L devices. The AlO x doping effect aligns well with previously reported data for 1L and FL MoS 2 and ReS 2 encapsulation.…”

Section: Introductionsupporting

confidence: 49%

Improved Current Density and Contact Resistance in Bilayer MoSe₂ Field Effect Transistors by AlO_x Capping

Somvanshi

Ber

Bailey

et al. 2020

ACS Appl. Mater. Interfaces

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Atomically thin semiconductors are of interest for future electronics applications, and much attention has been given to monolayer (1L) sulfides, such as MoS 2 , grown by chemical vapor deposition (CVD). However, reports on the electrical properties of CVD-grown selenides, and MoSe 2 in particular, are scarce. Here, we compare the electrical properties of 1L and bilayer (2L) MoSe 2 grown by CVD and capped by sub-stoichiometric AlO x . The 2L channels exhibit ∼20× lower contact resistance ( R C ) and ∼30× larger current density compared with 1L channels. R C is further reduced by >5× with AlO x capping, which enables improved transistor current density. Overall, 2L AlO x -capped MoSe 2 transistors (with ∼500 nm channel length) achieve improved current density (∼65 μA/μm at V DS = 4 V), a good I on / I off ratio of >10 6 , and an R C of ∼60 kΩ·μm. The weaker performance of 1L devices is due to their sensitivity to processing and ambient. Our results suggest that 2L (or few layers) is preferable to 1L for improved electronic properties in applications that do not require a direct band gap, which is a key finding for future two-dimensional electronics.

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Section: Introductionsupporting

confidence: 49%

Improved Current Density and Contact Resistance in Bilayer MoSe₂ Field Effect Transistors by AlO_x Capping

Somvanshi

Ber

Bailey

et al. 2020

ACS Appl. Mater. Interfaces

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“…However, during the synthesis process of MoSe 2 via chemical vapor transport (CVT) or chemical vapor deposition (CVD), uncontrolled defects states can be introduced in the MoSe 2 flakes, because of involving the high temperature and pressure environment to produce a single crystal mineral TMD. Therefore, the synthesized MoSe 2 FETs tend to randomly exhibit the characteristics of not only n‐type behavior but also ambipolar or p‐type behavior; as shown in previous results, it has been reported that CVD‐ or CVT‐grown MoSe 2 FETs can be ambipolar, n‐dominant, or p‐dominant transistors depending on the growth conditions. To enable the integration of CVD‐ or CVT‐synthesized MoSe 2 in practical devices, these inhomogeneous characteristics of MoSe 2 FETs should be unipolar.…”

supporting

confidence: 58%

n‐Type Doping Effect of CVD‐Grown Multilayer MoSe₂ Thin Film Transistors by Two‐Step Functionalization

Hong

et al. 2018

Adv Elect Materials

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Molybdenum diselenide (MoSe2) has attracted attention as a potential semiconductor platform. However, the as‐synthesized MoSe2 field‐effect transistors (FETs) tend to exhibit the arbitrary properties of n‐type, p‐type, or ambipolar behavior due to the uncontrolled growth condition. Here, two‐step functionalization is proposed to achieve n‐doping effect and long‐term stability in chemical vapor deposition (CVD)–grown MoSe2 FETs using oxygen plasma treatment followed by the deposition of an Al2O3 layer. After the two‐step surface functionalization procedure, three types of multilayer MoSe2 FETs are all converted to n‐type with the improvement of their electrical characteristics and stability; the n‐doped multilayer MoSe2 FETs exhibit an enhancement in field‐effect mobility from 12.23 to 31.57 cm2 V−1 s−1 and a 3 times higher Ion/Ioff, compared to pristine multilayer MoSe2 FETs. This enhancement of electric performance is attributed to the oxidation of topmost MoSe2 to interfacial MoOx with SeOx induced by the oxygen plasma treatment, as well as to the existence of fixed positive charges in deposited Al2O3. The functionalized devices exhibit excellent stability against stress, as confirmed with negative bias illumination stress tests for 7200 s. Moreover, an environmental stability test for 21 days reveals no degradation in electric performance of MoSe2 FETs.

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“…When the thickness of MoSe 2 continuously increased to about 7 layers, the transistor showed ambipolar behaviors . Furthermore, monolayer MoSe 2 could realize ambipolar charge transport by employing EDL technique …”

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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Ambipolar transport in CVD grown MoSe2 monolayer using an ionic liquid gel gate dielectric

Cited by 15 publications

References 23 publications

Improved Current Density and Contact Resistance in Bilayer MoSe₂ Field Effect Transistors by AlO_x Capping

Improved Current Density and Contact Resistance in Bilayer MoSe₂ Field Effect Transistors by AlO_x Capping

n‐Type Doping Effect of CVD‐Grown Multilayer MoSe₂ Thin Film Transistors by Two‐Step Functionalization

Recent Advances in Ambipolar Transistors for Functional Applications

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Ambipolar transport in CVD grown MoSe2 monolayer using an ionic liquid gel gate dielectric

Cited by 15 publications

References 23 publications

Improved Current Density and Contact Resistance in Bilayer MoSe2 Field Effect Transistors by AlOx Capping

Improved Current Density and Contact Resistance in Bilayer MoSe2 Field Effect Transistors by AlOx Capping

n‐Type Doping Effect of CVD‐Grown Multilayer MoSe2 Thin Film Transistors by Two‐Step Functionalization

Recent Advances in Ambipolar Transistors for Functional Applications

Contact Info

Product

Resources

About

Improved Current Density and Contact Resistance in Bilayer MoSe₂ Field Effect Transistors by AlO_x Capping

Improved Current Density and Contact Resistance in Bilayer MoSe₂ Field Effect Transistors by AlO_x Capping

n‐Type Doping Effect of CVD‐Grown Multilayer MoSe₂ Thin Film Transistors by Two‐Step Functionalization