Synthesis of 2D MoS_2(1−x)Se_2x semiconductor alloy by chemical vapor deposition

Abstract

Alloying/doping in two-dimensional (2D) materials is emerging as an increasingly important strategy due to the wide-range bandgap tunability and versatility of these materials.

Review of strategies toward the development of alloy two-dimensional (2D) transition metal dichalcogenides

“… Bandgap (eV) Semiconductor Type Synthesis Method Ref. MoS 2(1-x) Se 2x 0-1 atomic % 1.5–1.8 p-type CVD ( Yao et al., 2020 ; Dong et al., 2019 ) Mo (1-x) W x S 2 0-1 atomic % 1.8–2.01 – – ( Dong et al., 2019 ) Mo (1-x) W x Se 2 0-1 atomic % 1.5–1.7 – – ( Dong et al., 2019 ) WS 2(1-x) Se 2x 0-1 atomic % 1.7–2.01 – – ( Dong et al., 2019 ) WS 2x Se 2(1-x) 0.48 atomic % 3.5–3.9 p-type CVD ( Ko et al., 2018 ) WS 2(1-x) Te 2x ( 2H ) <0.5 atomic % 1.97–1.67 p-type CVD ( Wang et al., 2020d ) WS 2(1-x) Te 2x ( 1T ′) ≥0.5 atomic % 0 n-type CVD ( Wang et al., 2020d ) Mo x Re (1-x) S 2 ( 2H ) <0.3 atomic % – n-type CVD ( Deng et al., 2020 ) Mo x Re (1-x) S 2 ( 1T ′) ≥0.3 atomic % – p-type CVD ( Deng et al., 2020 ) …”

“…(ii-iii) HAADF-STEM images of monolayer 2H WS 1.66 Te 0.34 and 1T′ phase WS 0.92 Te 1.08 alloys ( Wang et al., 2020d ). (D) Schematic of synthesis method of TMDCs alloy (E) MoS 2(1-x) Se 2x Band energies at x ¼ 0, 0.20, 0.37, 0.55, and 1 ( Yao et al., 2020 ). …”

“… (D) Schematic of synthesis method of TMDCs alloy (E) MoS 2(1-x) Se 2x Band energies at x ¼ 0, 0.20, 0.37, 0.55, and 1 ( Yao et al., 2020 ). …”

“…Alloying Se in chalcogen site, Mo S 2(1-x) Se 2x resulted in p-type semiconductor for 0 to 1 atomic % with a bandgap of 1.82 to 1.53 eV using low-pressure CVD method ( Figure 3 D). Bandgap values decrease with Se doping in MoS 2 lattice as the Se occupies the highest occupied molecular orbital and lowest unoccupied orbital ( Figure 3 E) ( Yao et al., 2020 ). It is also reported to have less distortion energy of 0.06 eV, resulting in the valence band orbital and conduction band orbital having an increase or decrease monotonically with the dopant composition ( Dong et al., 2019 ).…”

Optoelectronic Properties of Atomically Thin MoxW(1−x)S2 Nanoflakes Probed by Spatially-Resolved Monochromated EELS

“…Concerning the electronic properties of 2D materials, tunable band gaps seem to have become crucial for the further development of electronic applications [24][25][26][27][28][29][30][31][32][33]. Most available 2D materials offer limited and rigid band gap values to work with (5.8 eV for monolayer BN [34][35][36][37] and 0 eV for monolayer graphene [38], for instance) and offer a limited versatility for electronic applications.…”