Long‐Term Stability Control of CVD‐Grown Monolayer MoS₂

Abstract

The structural stability of 2D transition metal dichalcogenide (TMD) formations is of particular importance for their reliable device performance in nano-electronics and opto-electronics. Recent observations show that the CVD-grown TMD monolayers are likely to encounter stability problems such as cracking or fracturing when they are kept under ambient conditions. Here, two different growth configurations are investigated and a favorable growth geometry is proposed, which also sheds light onto the growth mechanism and provides a solution for the stability and fracture formation issues for TMDs specifically for MoS 2 monolayers. It is shown that 18 months naturally and thermally aged MoS 2 monolayer flakes grown using specifically developed conditions, retain their stability. To understand the mechanism of the structural deterioration, two possible effective mechanisms, S vacancy defects and growth-induced tensile stress, are assessed by the first principle calculations where the role of S vacancy defects in obtaining oxidation resistant MoS 2 monolayer flakes is revealed to be rather more critical. Hence, these simulations, time-dependent observations and thermal aging experiments show that durability and stability of 2D MoS 2 flakes can be controlled by CVD growth configuration.Two-dimensional (2D) transition metal dichalcogenide (TMD) semiconductors such as monolayer or few-layer MoS 2 , WS 2 , MoSe 2 , etc. have attracted significant attention due to their potentially disruptive electronic and optical properties. In particular, researchers have put significant effort to adopt these materials in future optoelectronic and photonic applications. [1,2]

MoS2 Phototransistor Sensitized by Colloidal Semiconductor Quantum Wells

“…[ 39 ] Typical room‐temperature PL spectra obtained from monolayer MoS 2 [ 40 ] on the glass (Figure 1d) and Al 2 O 3 /Si (Figure 1e) are deconvoluted to the known excitonic features of MoS 2 , A‐ and B‐exciton and A‐trion peaks, by fitting Gaussian curves. [ 41 ] The center wavelengths of A‐exciton, B‐exciton, and A‐trion are found as ≈676, 632 and 697 nm for our MoS 2 on its grown substrate (glass) and ≈678, 642, and 691 nm for the transferred MoS 2 on the Al 2 O 3 /Si substrate, correspondingly. Here, as shown in Figure 1e, the A‐trion intensity is slightly increased after the transfer procedure, which can be attributed to the defects introduced unintentionally during the transfer procedure, as the PL characteristics of MoS 2 are very sensitive to the doping levels and defect densities.…”

“…The photogating effect in the layered materials occurs due to the consequence of long‐lived traps at the surface or interface, which are mainly induced during the growth process as S‐vacancies. [ 41 ] The decrease in the α exponent for the MoS 2 ‐CQWs device compared to the pristine MoS 2 device at all gate voltages suggest that the energy transfer from the CQWs to the MoS 2 layer is also coupled by the traps states of MoS 2 and results in an increased effect of the photogating.…”

TFT Channel Materials for Display Applications: From Amorphous Silicon to Transition Metal Dichalcogenides

“…Meanwhile, control over the growth conditions and growth geometry may also suppress a degradation of the synthesized sample (e.g., CVD‐grown sample). For example, MoS 2 grown at a low vapor concentration did not show any apparent changes in the properties during the aging owing to its small S vacancy concentration 141…”

Memristive Non-Volatile Memory Based on Graphene Materials

“…Currently, high-quality graphene materials with monocrystalline and polycrystalline structures are only reported to be grown by CVD and thermal desorption of Si from SiC single crystals [61], and notable progress was achieved in the deposition of graphene on metals [30,62,63]. In addition, although the growth of h-BN and TMD materials is also investigated, the growth of large-area monolayers or few-layer single crystals of h-BN and TMDs is still a major challenge [64,65]. Apart from CVD and ALD, the nucleation and growth approach was also investigated, showing that graphene single crystals could be deposited on metals like copper (Cu) and lithium (Li) [53,66].…”