High-performance n-type transistors based on CVD-grown large-domain trilayer WSe2

Abstract

Atomically thin layered tungsten diselenide (WSe2) has attracted tremendous research attention for its potential applications in next-generation electronics. This article reports the synthesis method of high-quality monolayer to trilayer WSe2 by molten-salt-assisted chemical vapor deposition. With the optimization of different types of molten salts and depths of corundum boat, large trilayer WSe2 films can be grown with domain size up to 80 µm for the first time. A systematic study of the electrical properties of the n-type field-effect transistor has been carried out based on WSe2 with the above three different layer thicknesses. The trilayer WSe2 devices exhibit higher drive current, mobility, on/off ratio, and lower contact resistance than both bilayer and monolayer counterparts. Moreover, short channel transistors using the trilayer WSe2 with a channel length of 230 nm have been fabricated, exhibiting an excellent on/off ratio up to 108 and a high current density of 187 µA/μm. This facile synthesis of high-quality large-area multilayer WSe2 provides a pathway for future high-performance two-dimensional electronic devices.

Single-crystalline WSe2 nanoflakes as efficient electrocatalysts

“…However, these methods often result in the incorporation of hetero-elements and formation of secondary phases. [24][25][26] To address challenges such as stoichiometry control and impurity reduction our study introduces a novel single-source precursor (SSP) with preformed tungstenselenide bonds. This molecular precursor was targeted for mild and efficient decomposition, bypassing issues linked to multiple precursors and ensuring controlled phase formation with specific stoichiometry, oxidation states, and purity.…”

“…This molecular precursor was targeted for mild and efficient decomposition, bypassing issues linked to multiple precursors and ensuring controlled phase formation with specific stoichiometry, oxidation states, and purity. [24][25][26] The optimal coordination of selenium-containing ligands around tungsten in the precursor stabilizes tungsten in the desired tetravalent (W(IV)) state, facilitating WSe 2 formation in a single decomposition step under mild conditions.…”

Non‐Volatile Reconfigurable p–n Junction Utilizing In‐Plane Ferroelectricity in 2D WSe2/α‐In2Se3 Asymmetric Heterostructures

“…Since the first experimental realization of the monoatomic graphene layer, [1] 2D structures have drawn enormous attention due to their exceptional properties such as high surface to volume ratio, tunable bandgap, [2,3] dangling-bonds free interface, DOI: 10.1002/adfm.202306682 high thermal and electrical conductivities, [4,5] chemical sensitivity, [6] etc. Among them, transition metal dichalcogenides (TMDCs), particularly ambipolar WSe 2 , show ultra-high photoresponsivity, [7] , high-speed chargetransfer dynamics, [8] and superior on-off ratio, [9,10] which makes it a promising material for novel optoelectronic devices. [11][12][13] Ever since the semiconductors' discovery, the p-n junction has become an essential circuit element in modern electronics.…”

Ultimate Limit in Optoelectronic Performances of Monolayer WSe2 Sloping-Channel Transistors

“…As the channel length increases from 20 to 230 nm, the I ON /I OFF increases from 680 to 10 8 , but the I ON decreases from 1.7 mA/μm to 0.2 mA/ μm. 39 The achievement of ultrahigh drive current and ultralow leakage current in our sloping-channel device demonstrates its potential to realize the trade-off between high-performance and low-power electronics.…”

“…We have summarized the normalized ON-current at V DS = 1 V for the varied 2D semiconductors and gate length, as depicted in Figure f. ,,− It is worthy pointing out that the bilayer WSe 2 transistor can achieve a higher ON-current of 1.7 mA/μm, but at the cost of reducing the I ON / I OFF value to less than 10 3 . As the channel length increases from 20 to 230 nm, the I ON / I OFF increases from 680 to 10 8 , but the I ON decreases from 1.7 mA/μm to 0.2 mA/μm . The achievement of ultrahigh drive current and ultralow leakage current in our sloping-channel device demonstrates its potential to realize the trade-off between high-performance and low-power electronics.…”