title: Establishment of 2D Crystal Heterostructures by Sulfurization of Sequential Transition Metal Depositions: Preparation, Characterization, and Selective Growth.
abstract: A nine-layer WS2/MoS2heterostructure is established on a sapphire substrate after sequential growth of large-area and uniform five- and four-layer MoS2and WS2films by using sulfurization of predeposited 1.0 nm molybdenum (Mo) and tungsten (W), respectively. By using the results obtained from the ultraviolet photoelectron spectroscopy and the absorption spectrum measurements of the standalone MoS2and WS2samples, a type-II band alignment is predicated for the WS2/MoS2heterostructure. Increasing drain currents and enhanced field-effect mobility value of the transistor fabricated on the heterostructure suggested that a channel with higher electron concentration compared with the standalone MoS2transistor channel is obtained with electron injection from WS2to MoS2under thermal equilibrium. Selective 2D crystal growth with (I) blank sapphire substrate, (II) standalone MoS2, (III) WS2/MoS2heterostructure, and (IV) standalone WS2was demonstrated on a single sapphire substrate. The results have revealed the potential of this growth technique for practical applications.
authors.affiliation: Graduate Institute of Electronics Engineering, National Taiwan University , No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan.|Research Center for Applied Sciences, Academia Sinica , No. 128, Sec. 2, Academia Road, Taipei 11529, Taiwan.
authors.forename: Chong-Rong
authors.initials: CR
authors.lastname: Wu
authors.affiliation: Research Center for Applied Sciences, Academia Sinica , No. 128, Sec. 2, Academia Road, Taipei 11529, Taiwan.
authors.forename: Xiang-Rui
authors.initials: XR
authors.lastname: Chang
authors.affiliation: Graduate Institute of Electronics Engineering, National Taiwan University , No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan.
authors.forename: Tung-Wei
authors.initials: TW
authors.lastname: Chu
authors.affiliation: Graduate Institute of Electronics Engineering, National Taiwan University , No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan.|Research Center for Applied Sciences, Academia Sinica , No. 128, Sec. 2, Academia Road, Taipei 11529, Taiwan.
authors.forename: Hsuan-An
authors.initials: HA
authors.lastname: Chen
authors.affiliation: Graduate Institute of Electronics Engineering, National Taiwan University , No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan.
authors.forename: Chao-Hsin
authors.initials: CH
authors.lastname: Wu
authors.affiliation: Graduate Institute of Electronics Engineering, National Taiwan University , No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan.|Research Center for Applied Sciences, Academia Sinica , No. 128, Sec. 2, Academia Road, Taipei 11529, Taiwan.
authors.forename: Shih-Yen
authors.initials: SY
authors.lastname: Lin
keywords: 2D crystal heterostructures; transition metal dichalcogenides