Long‐Term Stability Control of CVD‐Grown Monolayer MoS2. Issue 7 (18th March 2019)

• Record Type: Journal Article
• Authors: Şar, Hüseyin; Özden, Ayberk; Demiroğlu, İlker; Sevik, Cem; Perkgoz, Nihan K.; Ay, Feridun
• Is Part Of: Physica status solidi. Volume 13:Issue 7(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-03-18
• Subjects: aging -- chemical vapor deposition, cracks -- fracture -- long‐term stability -- monolayer MoS2 -- transition metal dichalcogenides; Solid state physics -- Periodicals; 530.4105
• DOI: 10.1002/pssr.201800687
• Languages: English
• ISSNs: 1862-6254

Abstract

Abstract : The structural stability of 2D transition metal dichalcogenide (TMD) formations is of particular importance for their reliable device performance in nano‐electronics and opto‐electronics. Recent observations show that the CVD‐grown TMD monolayers are likely to encounter stability problems such as cracking or fracturing when they are kept under ambient conditions. Here, two different growth configurations are investigated and a favorable growth geometry is proposed, which also sheds light onto the growth mechanism and provides a solution for the stability and fracture formation issues for TMDs specifically for MoS2 monolayers. It is shown that 18 months naturally and thermally aged MoS2 monolayer flakes grown using specifically developed conditions, retain their stability. To understand the mechanism of the structural deterioration, two possible effective mechanisms, S vacancy defects and growth‐induced tensile stress, are assessed by the first principle calculations where the role of S vacancy defects in obtaining oxidation resistant MoS2 monolayer flakes is revealed to be rather more critical. Hence, these simulations, time‐dependent observations and thermal aging experiments show that durability and stability of 2D MoS2 flakes can be controlled by CVD growth configuration. Abstract : The proposed growth geometry provides a solution for the stability–fracture issue for CVD‐grown transition metal dichalcogenides. A clear difference is unveiled regarding the mechanical stability of the flakes grown by horizontal (HO, proposed by the authors) and face down (FD, commonly used) growth approaches, where the FD‐grown flakes spontaneously crack but HO flakes remain unchanged and keep their as‐grown structures for the duration of their observation, exceeding 18 months.