Robust enhancement of valley polarization and quantum yield in composition grading lateral heterostructure of MoS 2-WS 2 monolayer

Kang, Mengke1; Zhang, Cheng2,3; Mu, Congpu1; Zhai, Kun1; Xue, Tianyu1; Wang, Bochong1; Wen, Fusheng1; Cheng, Yingchun1; Xiang, Jianyong1; Dai, Jun-Feng2,3,4; Nie, Anmin1; Liu, Zhongyuan1

2024-02-01

10.1016/j.pnsc.2024.02.014

PROGRESS IN NATURAL SCIENCE-MATERIALS INTERNATIONAL   影响因子和分区

1002-0071

1745-5391

Valley degeneracy can be broken owing to the strong spin -orbit coupling in two-dimensional transition metal dichalcogenides (2D-TMDCs). Valley -dependent interaction of carriers in TMDCs with different circular polarizations of light offers valley degree -of -freedom besides charge and spin to carry information. Thus, bandgap engineering of 2D-TMDCs plays a critical role in developing practical valleytronic devices. Hereby, we demonstrate a great enhancement in quantum yield as well as polarization of monolayer MoS 2 achieved by gradually alloying W atoms in MoS 2 . By appropriately setting a time offset between the evaporation of MoO 3 and WO 3 precursors during chemical vapor deposition, a compositionally graded heterostructure of MoS 2 -WS 2 monolayer can be readily grown at large scale. Raman and transmission electron microscopy measurements demonstrate that the interface possesses a steep gradient in composition, spanning from MoS 2 to WS 2 over a length -2 mu m. Compared to pure monolayer MoS 2 , the photoluminescence intensity at the compositionally graded interface of Mo 1-x W x S 2 was observed to increase by a factor of 16 owing to the effective separation of photogenerated carriers by the built-in electric field. Particularly, a remarkably high polarization of 70% at 16 K is demonstrated for the compositionally graded interface of Mo 1-x W x S 2 , which is -1.4 times larger than that in MoS 2 and is attributed to the combined effect of the alloyed structure and graded bandgap. Such an engineering scheme with a graded bandgap offers new approach for the development of high -ef ficiency valleytronics devices.

Transition metal dichalcognide monolayer Compositionally graded in-plane hetero-structure Chemical vapor deposition Valley polarization Quantum yield

SCI ; EI

英语

通讯

Natural Science Foundation of China["52090022","51972280","11974159"] ; Natural Science Foundation for Distinguished Young Scholars of Hebei Province[E2020203085]

Materials Science ; Science & Technology - Other Topics

Materials Science, Multidisciplinary ; Multidisciplinary Sciences

WOS:001222937600001

ELSEVIER SCIENCE INC

Web of Science

1.Yanshan Univ, Ctr High Pressure Sci, State Key Lab Metastable Mat Sci & Technol, Qinhuangdao 066004, Peoples R China
2.Southern Univ Sci & Technol, Shenzhen Inst Quantum Sci & Engn, Shenzhen 518055, Peoples R China
3.Southern Univ Sci & Technol, Dept Phys, Shenzhen 518055, Peoples R China
4.Shenzhen Key Lab Quantum Sci & Engn, Shenzhen 518055, Peoples R China

Kang, Mengke,Zhang, Cheng,Mu, Congpu,et al. Robust enhancement of valley polarization and quantum yield in composition grading lateral heterostructure of MoS 2-WS 2 monolayer[J]. PROGRESS IN NATURAL SCIENCE-MATERIALS INTERNATIONAL,2024,34(1).

Kang, Mengke.,Zhang, Cheng.,Mu, Congpu.,Zhai, Kun.,Xue, Tianyu.,...&Liu, Zhongyuan.(2024).Robust enhancement of valley polarization and quantum yield in composition grading lateral heterostructure of MoS 2-WS 2 monolayer.PROGRESS IN NATURAL SCIENCE-MATERIALS INTERNATIONAL,34(1).

Kang, Mengke,et al."Robust enhancement of valley polarization and quantum yield in composition grading lateral heterostructure of MoS 2-WS 2 monolayer".PROGRESS IN NATURAL SCIENCE-MATERIALS INTERNATIONAL 34.1(2024).