Position-Selective Growth of 2D WS₂-Based Vertical Heterostructures via a One-Step CVD Approach

Abstract

Vertical heterostructures of two-dimensional (2D) transition metal dichalcogenides (TMDCs) provide a prospective foreground for practical applications via combining novel physical characteristics that are distinguished from those of traditional counterparts. Here, we report the position-selective growth of 2D WS 2 -based vertical heterostructures, including WS 2 /MoS 2 , WS 2 /MoS 2 -Mo 0.42 W 0.58 S 2 , WS 2 /MoS 2 -Mo 1−x W x S 2 (0.4 ≤ x ≤ 0.85), and WS 2 /Mo 1−x W x S 2 (0 ≤ x ≤ 0.76), with the WS 2 monolayer as the top layer by a one-step chemical vapor deposition (CVD) method. Systematical Raman and photoluminescence (PL) characterizations corroborate that position-dependent vertical heterostructures exhibit a significant relationship between structural/optical characteristics and compositions. A possible growth mechanism of various 2D WS 2 -based heterostructures at different deposition regions is discussed based on the variation of metallic atoms along the gas flow direction. The current work supplies a promising and efficient strategy to fabricate complex heterostructures composed of various TMDCs, which is a crucial step to develop functional optoelectronic applications.

Stacking‐Engineered Heterostructures in Transition Metal Dichalcogenides

“…The quenching of both interlayer PL emissions in overlapped HSs originates from charge separation between the monolayers as a result of the formation of a type II heterobilayer, as presented in Figure 8b. [105][106][107][108] Another possible source of abnormal intralayer exciton activity is the quality of the sample itself. As shown in Figure 8c, defects and intrusions are common in the heterojunctions formed during the stacking process (assembly or growth), and thus the interlayer distance varies as a function of position, so that excitons behave abnormally.…”

“…b) Reproduced with permission. [ 107 ] Copyright 2019, American Chemical Society. c,d) Reproduced with permission.…”

“…Copyright 2016, American Chemical Society. b) Reproduced with permission [107]. Copyright 2019, American Chemical Society.…”

Recent progress in optoelectronic applications of hybrid 2D/3D silicon-based heterostructures

“…CVD is the most popular technique for preparing high-purity and high-performance films. Some heterostructures can be formed by growing low-dimensional materials directly on the substrate via CVD technology [35,36]. In the process of CVD, one or more vapor source atoms or molecules are carried by carrier gas in the chamber, and the desired film will be formed on the substrate surface through chemical reaction.…”

Spontaneous interlayer compression in commensurately stacked van der Waals heterostructures

“…Experiments combine ML materials (graphene, black phosphorus, hexagonal boron-nitride, MoS 2 , etc.) into heterostructure devices, either by creating lateral junctions via in-plane covalent bonding [9] or by growing or stacking them vertically [10]. These devices are used as biosensors [11], field-effect transistors [12], photo detectors [13], and electrooptical devices [14][15][16][17].…”