High-Mobility InSe Transistors: The Role of Surface Oxides

Ho, Po-Hsun; Chang, Young‐Chae; Chu, Yu–Cheng; Li, Min-Ken; Tsai, Che-An; Wang, Wei Hua; Ho, Ching‐Hwa; Chen, Chun-Wei; Chiu, Po‐Wen

doi:10.1021/acsnano.7b03531

Cited by 197 publications

(214 citation statements)

References 36 publications

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“…Moreover, considering that is measured in a two-terminal configuration where contact resistance is relevant, the observed high mobility suggests a high contact quality. We note that the two-terminal mobility in our InSe device is higher than the previously reported value, [8][9]37 increases with the decreasing T, indicating a metallic T dependence. We note that the metallic behavior arises at a small carrier density of 9 × 10 11 cm -2 , which is smaller than that of highperformance MoS2 devices.…”

Section: Resultscontrasting

confidence: 79%

“…Figure 3c shows the dependence of for sample A with an IIL, yielding a barrier height of Φ = 50 meV, which is comparable to the previously reported low barrier height of InSe. 9 In comparison, sample B exhibits a larger barrier height, Φ = 170 meV, as shown in Figure 3d. We note that because the calculation of mobility in two-terminal geometry is related to the value of contact resistance, the small Φ observed in samples with an IIL can lead to the extracted high mobility aforementioned.…”

Section: Mevmentioning

confidence: 90%

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High-Performance InSe Transistors with Ohmic Contact Enabled by Nonrectifying Barrier-Type Indium Electrodes

Huang

Chen

et al. 2018

ACS Appl. Mater. Interfaces

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The electrical contact to two-dimensional (2D) semiconductor materials is decisive to the electronic performance of 2D semiconductor field-effect devices (FEDs). The presence of a Schottky barrier often leads to a large contact resistance, which seriously limits the channel conductance and carrier mobility measured in a two-terminal geometry. In contrast, Ohmic contact is desirable and can be achieved by the presence of a nonrectifying or tunneling barrier. Here, we demonstrate that a nonrectifying barrier can be realized by contacting indium (In), a low work function metal, with layered InSe because of a favorable band alignment at the In-InSe interface. The nonrectifying barrier is manifested by Ohmic contact behavior at T = 2 K and a low barrier height, Φ = 50 meV. This Ohmic contact enables demonstration of an on-current as large as 410 μA/μm, which is among the highest values achieved in FEDs based on layered semiconductors. A high electron mobility of 3700 and 1000 cm/V·s is achieved with the two-terminal In-InSe FEDs at T = 2 K and room temperature, respectively, which can be attributed to enhanced quality of both conduction channel and the contacts. The improvement in the contact quality is further proven by an X-ray photoelectron spectroscopy study, which suggests that a reduction effect occurs at the In-InSe interface. The demonstration of high-performance In-InSe FEDs indicates a viable interface engineering method for next-generation, 2D semiconductor-based electronics.

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Section: Resultscontrasting

confidence: 79%

Section: Mevmentioning

confidence: 90%

High-Performance InSe Transistors with Ohmic Contact Enabled by Nonrectifying Barrier-Type Indium Electrodes

Huang

Chen

et al. 2018

ACS Appl. Mater. Interfaces

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“…In all cases we obtain remarkably low values of the order of 1 cm 2 V −1 s −1 . This result is highly unexpected in view of recent experimental reports on high mobility in 2D InSe [1][2][3][4]. We note, however, that our finding is solely applicable to free-standing InSe single Table I with the corresponding conductivity values.…”

supporting

confidence: 63%

Strong Electron-Phonon Coupling and its Influence on the Transport and Optical Properties of Hole-Doped Single-Layer InSe

Lugovskoi¹,

Katsnelson

Руденко

2019

Phys. Rev. Lett.

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We show that hole states in recently discovered single-layer InSe are strongly renormalized by the coupling with acoustic phonons. The coupling is enhanced significantly at moderate hole doping (∼10 13 cm −2 ) due to hexagonal warping of the Fermi surface. While the system remains dynamically stable, its electron-phonon spectral function exhibits sharp low-energy resonances, leading to the formation of satellite quasiparticle states near the Fermi energy. Such many-body renormalization is predicted to have two important consequences. First, it suppresses significantly charge carrier mobility reaching ∼1 cm 2 V −1 s −1 at 100 K in free-standing sample. Second, it gives rise to unusual temperature-dependent optical excitations in the mid-infrared region. Relatively small charge carrier concentrations and realistic temperatures suggest that these excitations may be observed experimentally.Two-dimensional (2D) indium selenide (InSe) is a recently discovered semiconductor receiving considerable attention because of its attractive electronic properties. Thin films InSe have been proposed to be suitable for field-effect transistor applications due to their high carrier mobilities, reported to exceed 10 3 cm 2 V −1 s −1 at room temperature [1][2][3][4]. Other interesting properties of this material include tunable band gap [5-8], fullydeveloped quantum Hall effect [2], anomalous optical response [2,5,9,10], superior flexibility [11], as well as excellent thermal [12,13] and thermoelectric [14] characteristics. These observations, along with its ambient stability [15], make low-dimensional InSe an appealing candidate for numerous practical applications [16].Single-layer (SL) InSe is a layered semiconductor with an indirect energy gap in the visible range. Its electronic structure is characterized by peculiar flat regions in the valence band [17], giving rise to a giant van Hove singularity in the hole density of states [18,19]. This feature is known as a "Mexican-hat"-like band, and has been predicted for the whole family of In 2 X 2 and Ga 2 X 2 (X=S,Se,Te) compounds [17,20]. Interestingly, this peculiar shape evolves into the conventional parabolic band with increasing material's thickness, as has been theoretically predicted for InSe [18,21] and recently confirmed by angular resolved photoemission spectroscopy [22]. This observation makes ultrathin InSe films especially attractive for further studies. The interest to flat-band materials is motivated by exotic physical properties of such systems, closely related to various many-body instabilities and strong correlation effects [23][24][25][26][27]. Recent experimental discovery of flat bands and associated many-body phenomena including superconductivity in magic-angle twisted bilayer graphene [28,29] enhances enormously the interest to the problem.Electron-phonon interaction in the case of narrow bands can be dramatically different from the conven-tional case and can play a more important role. In particular, a strong electron-phonon coupling in the magicangle twisted b...

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“…[10][11][12] Previous work has been performed to improve the mobility of InSe field-effect transistors (FETs) and other 2D material-based FETs. [13][14][15] For instance, (1) Heterojunction structure, 16 (2) high-k dielectric, 1,13 (3) high-k encapsulation, 17 and (4) Chemical and physical interface engineering 15,18,19 have been used to enhance the carrier mobilities of 2D materials based FETs. However, in addition to the carrier mobility of FETs, electrical stability is another extremely important factor in ensuring device reliability in practical applications.…”

Section: Introductionmentioning

confidence: 99%

Stable InSe transistors with high-field effect mobility for reliable nerve signal sensing

Jiang

et al. 2019

npj 2D Mater Appl

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Among two-dimensional layered semiconductors, indium selenide (InSe) is one of the most promising materials with absolute advantages in field-effect transistors (FETs) because of its high electron mobility and stable material properties. Some work has been performed to improve the mobility of InSe FETs. However, in practical applications, electrical stability of FETs is another essential factor to guarantee the performance of the electronic system. Here, we show a highly stable InSe FET with a field-effect mobility of 1200 cm 2 /V·s in the practical working regime. The bottom-gate staggered InSe FET was fabricated with a polymethyl methacrylate (PMMA)/HfO 2 dual-layer gate dielectric and PMMA back-channel encapsulation. The hysteresis was maintained at 0.4 V after 30 days of storage under normal ambient conditions, and the threshold voltage shift was retained at 0.6 V with a gate stress V GS of 10 V, which represents the best electrical stability reported to date. Its high mobility and electrical stability enable reliable detection of the weak nerve action potential at a low power consumption. High-performance InSe FETs expand their promising applications in flexible and in situ real-time intelligent nerve action potential recording.

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High-Mobility InSe Transistors: The Role of Surface Oxides

Cited by 197 publications

References 36 publications

High-Performance InSe Transistors with Ohmic Contact Enabled by Nonrectifying Barrier-Type Indium Electrodes

High-Performance InSe Transistors with Ohmic Contact Enabled by Nonrectifying Barrier-Type Indium Electrodes

Strong Electron-Phonon Coupling and its Influence on the Transport and Optical Properties of Hole-Doped Single-Layer InSe

Stable InSe transistors with high-field effect mobility for reliable nerve signal sensing

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