Improved Performances of CVD‐Grown MoS₂ Based Phototransistors Enabled by Encapsulation

Abstract

MoS2 as a semiconducting 2D material has been a promising candidate for the next generation of optoelectronics due to its atomic thickness, mechanical flexibility, complementary metal‐oxide‐semiconductor compatibility, and large‐scale manufacturing. However, the poor quality such as low mobility and numerous defects has much affected the corresponding device performances, which has limited their wide applications. Here, an effective strategy is proposed to significantly improve the quality of the chemical vapor deposition (CVD)‐grown monolayer MoS2 by the encapsulation technique with atomic layer deposition Al2O3. Benefiting from the passivation of defects and suppression of charge Coulomb scattering, the mobility can be improved by more than one order of magnitude, reaching up to 62.5 cm2 Vs−1. As a result, the photodetection performances in terms of response time, responsivity, and detectivity are also improved up to 20 ms, 1.1 × 104 A W−1, and 3.1 × 1012 Jones, respectively. The developed encapsulation technique here for the improvement of film quality and device performance can further enable the practical application of large‐scale 2D materials‐based electronics and photodetectors.

Reconfigurable carrier type and photodetection of MoTe2 of various thicknesses by deep ultraviolet light illumination

“…1d shows the Raman spectrum of MoTe 2 obtained using a Renishaw microspectrometer with a laser wavelength of 514 nm and an optical intensity of 1 mW cm À2 . Three vibrational modes were observed, namely, A 1 g , E 2g 1 and B 2g…”

“…Recently, two-dimensional (2D) nanomaterials have gained signicant attention because of their unique optical and electrical properties. [1][2][3] Graphene has been the focus of modern research in the past few years because of its high intrinsic electron mobility of 200 000 cm 2 V s À1 and high thermal conductivity of approximately 4400 to 5780 W m K À1 at room temperature. 4,5 In addition, the transmittance of light was found to be 97.7% at 550 nm owing to the small thickness of a single layer.…”

MoS2 as a Co-Catalyst for Photocatalytic Hydrogen Production: A Mini Review

“…[ 42 , 43 , 44 ]. Single layers, multilayers, nanoparticles, and quantum dots of MoS 2 have also been reported [ 45 , 46 , 47 , 48 ]. Continued efforts have been reported for the fabrication of MoS 2 nanomaterials via the top-down and bottom-up strategies [ 16 , 17 , 18 , 19 , 28 , 29 , 30 , 31 , 40 , 41 , 42 , 43 , 44 ].…”

“…Due to the layered structure and van der Waals interactions, MoS 2 nanosheets can be easily prepared through the exfoliation method. Mechanical, chemical, electrochemical, and liquid-phase exfoliation processes have been reported for the synthesis of MoS 2 nanosheets [ 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 ]. For example, in the mechanical exfoliation technique, the suitable MoS 2 flakes are peeled off from the bulk crystal of MoS 2 using adhesive tape and shifted onto a specific substrate [ 46 , 53 ].…”

Modulated Photoluminescence of Single-Layer MoS2 on Various Rutile TiO2 Surfaces: Implications for Photocatalytic Applications

“…As a representative of transition metal dichalcogenides (TMDs), MoS 2 has been widely studied for its distinguished optical and electronic properties. − It is well known that monolayer MoS 2 has a direct band gap of 1.90 eV, while bulk MoS 2 has an indirect band gap of 1.3 eV. , Concomitantly, the photoluminescence (PL) intensity of monolayer MoS 2 is 10 times higher than that of bulk MoS 2 . , Therefore, there has been increasing interest in tailoring the PL of monolayer MoS 2 via electrical gating, electrochemical control, and piezoelectric manipulation methods. − In addition, MoS 2 has a sufficiently large current on/off ratio (>10 10 ) and ideal subthreshold swing (∼60 mV dec –1 ), which endows it with promising applications in field-effect transistors, photoelectric devices, valley electronics, and energy storage devices. − These attractive aspects hence provoked large efforts in developing ways to obtain high-quality monolayer MoS 2 , wherein the chemical vapor deposition (CVD) strategy has been demonstrated as an efficient and reliable method to synthesize high-quality two-dimensional materials (2DMs) including MoS 2 on arbitrary substrates. − This strategy usually works at high temperatures far beyond the desorption point of common contaminants, and thus is capable of achieving a clean interface and an intimate contact between the fabricated film and the substrate. On the other hand, however, high synthetic temperatures also make it a challenge to grow 2DMs on functional materials with less stability.…”