Layer-controlled precise fabrication of ultrathin MoS₂ films by atomic layer deposition

Abstract

Monolayer and/or atomically thin transition metal dichalcogenides cover a wide range of two-dimensional (2D) materials, whose fascinating semiconducting and optical properties have made them promising candidate materials for optoelectronic devices. Controllable growth of these materials is critical for their device applications. By using MoCl and HS as precursors, monolayer and ultrathin molybdenum disulfide (MoS) films with controlled lamellar structure have been directly built layer by layer on SiO substrates without being followed by high-temperature annealing. Furthermore, the thickness of MoS films can be precisely regulated by applying different atomic layer deposition (ALD) cycles. Once an ALD cycle is applied, one molecular layer of MoS material will be 'added' on the substrate or original existing MoS films. At the initial stage (one to three ALD cycles), the density of MoS materials increases with an increase in ALD cycles, while a large area of continuous MoS film on the substrate can be obtained when four or more ALD cycles are applied. In this way, excellent triangular crystals of MoS with controlled atomic size in thickness and a highly oriented hexagonal crystal structures can be obtained by applying definite ALD cycles.

Structure and optical properties of 2D layered MoS2 crystals implemented with novel friction induced crystal growth

“…26 The FWHMs of the E 1 2g peaks for MoS 2 grown on SUS430 and Ge(100) substrates are 2.6 cm -1 and 3.4 cm -1 , respectively, and that of 5 layers of CVD and atomic layer deposition (ALD) grown MoS 2 is 10 cm -1 . 27,28 This suggests that the crystalline quality of the friction induced MoS 2 is good.…”

Interface Characterization and Control of 2D Materials and Heterostructures

“…A detailed perspective article summarizes the precursors used for different 2D materials. The growth of 2D materials directly via ALD, however, has been limited to TMDCs . In this context, ALD growth offers advantages over CVD in terms of growth temperature (as low as 60 °C) and scalability, although postgrowth annealing is typically required to improve crystallinity.…”

Recent progress in atomic layer deposition of molybdenum disulfide: a mini review

“…Our group has been able to obtain monolayer MoS 2 directly by ALD, and the thickness of MoS 2 can be locally controlled layer by layer [36,39,40]. In this review, both the research progress in ALD of MoS 2 and the application prospect of the obtained MoS 2 as an electrochemical catalysator are shown.…”

“…According to Fig. 1, where recent research progress in the preparation of MoS 2 by CVD [14][15][16][17][18][19][21][22] and ALD [29][30][31][32][33][34][35][36][37][38] is shown, CVD contains two different means. One is the thermal vapor sulfurization where the MoS 2 film is obtained by sulfurizing the pre-deposited molybdenum film at high temperature.…”