Multi-layer WSe 2 field effect transistor with improved carrier-injection contact by using oxygen plasma treatment

Kang, Won-Mook; Lee, Sung-Tae; Cho, In-Tak; Park, Tae Hyung; Shin, Hyeonwoo; Hwang, Cheol Seong; Lee, Changhee; Park, Byung‐Gook; Lee, Jong-Ho

doi:10.1016/j.sse.2017.10.008

Cited by 45 publications

(33 citation statements)

References 28 publications

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“…Lin and co-workers proposed that native chalcogen defect generation through H 2 plasma treatment could introduce stable n-type doping in MoS 2 . Similar results were reported by Tosun et al , It was also reported that oxygen or nitrogen plasma treatment could repair the structural defects, offer catalytic effect, or achieve other interesting properties to improve the performance of 2D dichalcogenide-based electrical and optoelectronic devices. − While plasma treatment was effective in modifying the electrical properties, the use of reactive gas (such as NH 3 , N 2 , or O 2 ) changed the chemical composition and degraded the optoelectronic properties of 2D semiconductors. As an inert gas, argon can be used for plasma treatment to avoid the chemical reaction.…”

Section: Introductionsupporting

confidence: 67%

“…However, the ion beam bombardment produced a remarkable structural damage to the upper three to five WS 2 layers, indicating that this technique was not suitable for treating monolayer materials. Besides, previous studies attributed the enhanced conductivity in plasma-treated 2D semiconductors to the lowered barrier height with metal electrodes. , Nonetheless, the mechanism for the enhanced carrier mobility remains unclear. Further research is required to develop a nondestructive plasma treatment technique and to unravel the physical mechanism of plasma-induced changes in electrical properties.…”

Section: Introductionmentioning

confidence: 99%

“…Besides, previous studies attributed the enhanced conductivity in plasma-treated 2D semiconductors to the lowered barrier height with metal electrodes. 22,24 Nonetheless, the mechanism for the enhanced carrier mobility remains unclear. Further research is required to develop a nondestructive plasma treatment technique and to unravel the physical mechanism of plasma-induced changes in electrical properties.…”

Section: ■ Introductionmentioning

confidence: 99%

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Reduced Turn-On Voltage and Boosted Mobility in Monolayer WS₂ Transistors by Mild Ar⁺ Plasma Treatment

Hou

Chen

et al. 2020

ACS Appl. Mater. Interfaces

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Monolayer two-dimensional transition-metal dichalcogenides, such as tungsten disulfide (WS 2 ), are regarded as promising candidates for optoelectronic and electronic applications. Although theoretical calculations have predicted outstanding electronic properties of WS 2 , the performance of WS 2 -based electronic devices is still limited by the relatively high Schottky barrier and low carrier mobility. In this work, low-energy argon (Ar + ) plasma treatment was used as a nondestructive preconditioning technique to tailor the electrical properties of the WS 2 monolayer grown by chemical vapor deposition. Photoluminescence and Raman spectroscopy were used to monitor the modified optical properties of WS 2 with increasing plasma treatment time. An improved electrical conductivity was observed after a short-time plasma treatment. The physical mechanism was further revealed by a comparative study between topelectrode and bottom-electrode devices and simulation based on the density functional theory. It is concluded that mild Ar + plasma treatment can effectively lower the Schottky barrier height and the effective mass of carriers, which reduces the turn-on voltage and enhances the mobility, respectively. However, if the processing time is too long, the WS 2 lattice structure will be destroyed. This work has provided an effective method for manipulating the Schottky barrier and mobility of monolayer WS 2 transistors and paves the way for developing high-performance electronic devices based on 2D semiconductors. KEYWORDS: tungsten disulfide (WS 2 ), WS 2 field-effect transistors, Ar + plasma treatment, Schottky barrier (SB), work function

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Section: Introductionsupporting

confidence: 67%

Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Reduced Turn-On Voltage and Boosted Mobility in Monolayer WS₂ Transistors by Mild Ar⁺ Plasma Treatment

Hou

Chen

et al. 2020

ACS Appl. Mater. Interfaces

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“…Consequently, TMDC layers-based electronic devices are being investigated extensively 15,16 . On the other hand, after the lithography, the removal of resist residues, surface passivation or metal-semiconductor contact improvement must be done using the correct solvent rinsing 17 and plasma exposure 18,19 for each TMDC compound. To further exploit TMDC materials at the nanoscale a mature development of nanolithographic strategies to fabricate TMDC nanopatterns with feature sizes below or approximate to the quantum and sub-wavelength regimes will give rise to the study of new fundamental phenomena 20 .…”

Section: Introductionmentioning

confidence: 99%

Direct Patterning of p-Type-Doped Few-layer WSe₂ Nanoelectronic Devices by Oxidation Scanning Probe Lithography

Dago

Ryu

Palomares

et al. 2018

ACS Appl. Mater. Interfaces

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Direct, robust and high resolution patterning methods are needed to downscale the lateral size of 2D materials to observe new properties and to optimize the overall processing of these materials. In this work we report a fabrication process where the initial micro-channel of a few-layer WSe 2 field-effect transistor is treated by oxygen plasma to form a self-limited oxide layer on top of the flake. This thin oxide layer has a double role here. First, it induces the so called p-doping effect in the device. Second, it enables the fabrication of oxide nanoribbons with controlled width and depth by oxidation scanning probe lithography (o-SPL). After the removal of the oxides by deionized H 2 O etching, a nanoribbon-based field effect transistor is produced. Oxidation SPL is a direct writing technique that minimizes the use of resists and lithographic steps. We have applied this process to fabricate a 5 nm thick WSe 2 field-effect transistor where the channel consists in an array of 5 parallel 350 nm halfpitch nanoribbons. The electrical measurements show that the device presents an improved conduction level compared to the starting thin layer transistor and a positive threshold voltage shift associated to the p-doping treatment. The method enables to pattern devices with sub-50 nm feature sizes. We have patterned an array of 10 oxide nanowires with 36 nm half-pitch by oxidation SPL.

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“…Therefore, a simple and practical doping approach with a complete compatibility with existing semiconductor processes is demanded in producing the TMDs based p-n junction with low metal contact resistance. For the past few years, the plasma treatment has been proven to be effective in fine-tuning the electrical properties of TMDs by means of plasma-induced structural defects or surface reaction. − …”

mentioning

confidence: 99%

An Ultrafast WSe₂ Photodiode Based on a Lateral p-i-n Homojunction

et al. 2021

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High-quality homogeneous junctions are of great significance for developing transition metal dichalcogenides (TMDs) based electronic and optoelectronic devices. Here, we demonstrate a lateral p-type/intrinsic/n-type (p-i-n) homojunction based multilayer WSe2 diode. The photodiode is formed through selective doping, more specifically by utilizing self-aligning surface plasma treatment at the contact regions, while keeping the WSe2 channel intrinsic. Electrical measurements of such a diode reveal an ideal rectifying behavior with a current on/off ratio as high as 1.2 × 106 and an ideality factor of 1.14. While operating in the photovoltaic mode, the diode presents an excellent photodetecting performance under 450 nm light illumination, including an open-circuit voltage of 340 mV, a responsivity of 0.1 A W–1, and a specific detectivity of 2.2 × 1013 Jones. Furthermore, benefiting from the lateral p-i-n configuration, the slow photoresponse dynamics including the photocarrier diffusion in undepleted regions and photocarrier trapping/detrapping due to dopants or doping process induced defect states are significantly suppressed. Consequently, a record-breaking response time of 264 ns and a 3 dB bandwidth of 1.9 MHz are realized, compared with the previously reported TMDs based photodetectors. The above-mentioned desirable properties, together with CMOS compatible processes, make this WSe2 p-i-n junction diode promising for future applications in self-powered high-frequency weak signal photodetection.

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Multi-layer WSe 2 field effect transistor with improved carrier-injection contact by using oxygen plasma treatment

Cited by 45 publications

References 28 publications

Reduced Turn-On Voltage and Boosted Mobility in Monolayer WS₂ Transistors by Mild Ar⁺ Plasma Treatment

Reduced Turn-On Voltage and Boosted Mobility in Monolayer WS₂ Transistors by Mild Ar⁺ Plasma Treatment

Direct Patterning of p-Type-Doped Few-layer WSe₂ Nanoelectronic Devices by Oxidation Scanning Probe Lithography

An Ultrafast WSe₂ Photodiode Based on a Lateral p-i-n Homojunction

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Multi-layer WSe 2 field effect transistor with improved carrier-injection contact by using oxygen plasma treatment

Cited by 45 publications

References 28 publications

Reduced Turn-On Voltage and Boosted Mobility in Monolayer WS2 Transistors by Mild Ar+ Plasma Treatment

Reduced Turn-On Voltage and Boosted Mobility in Monolayer WS2 Transistors by Mild Ar+ Plasma Treatment

Direct Patterning of p-Type-Doped Few-layer WSe2 Nanoelectronic Devices by Oxidation Scanning Probe Lithography

An Ultrafast WSe2 Photodiode Based on a Lateral p-i-n Homojunction

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Product

Resources

About

Reduced Turn-On Voltage and Boosted Mobility in Monolayer WS₂ Transistors by Mild Ar⁺ Plasma Treatment

Reduced Turn-On Voltage and Boosted Mobility in Monolayer WS₂ Transistors by Mild Ar⁺ Plasma Treatment

Direct Patterning of p-Type-Doped Few-layer WSe₂ Nanoelectronic Devices by Oxidation Scanning Probe Lithography

An Ultrafast WSe₂ Photodiode Based on a Lateral p-i-n Homojunction