Batch growth of high-mobility (μFE > 10 cm2V-1s-1) molybdenum disulfide (MoS2) films can be achieved by means of the chemical vapor deposition (CVD) method at high temperatures (>500 °C) on rigid substrates. Although high-temperature growth guarantees film quality, time- and cost-consuming transfer processes are required to fabricate flexible devices. In contrast, low-temperature approaches (<250 °C) for direct growth on polymer substrates have thus far achieved film growth with limited spatial homogeneity and electrical performance (μFE is unreported). The growth of a high-mobility MoS2 film directly on a polymer substrate remains challenging. In this study, a novel low-temperature (250 °C) process to successfully overcome this challenge by kinetics-controlled metal-organic CVD (MOCVD) is proposed. Low-temperature MOCVD was achieved by maintaining the flux of an alkali-metal catalyst constant during the process; furthermore, MoS2 was directly synthesized on a polyimide (PI) substrate. The as-grown film exhibits a 4 in. wafer-scale uniformity, field-effect mobility of 10 cm2V-1s-1, and on/off ratio of 105, which are comparable with those of high-temperature-grown MoS2. The directly fabricated flexible MoS2 field-effect transistors demonstrate excellent stability of electrical properties following a 1000 cycle bending test with a 1 mm radius.
Bibliographical noteFunding Information:
This work was supported by the Technology Innovation Program (project no. 10062161, Direct low-temperature synthesis of two-dimensional materials and heterostructure on flexible substrate for next-generation high-mobility electronic devices), funded by the Ministry of Trade, Industry, and Energy (MOTIE, Korea), and was supported by development of semiconductor measurement equipment technology funded by Korea Research Institute of Standards and Science (KRISS-2019-GP2019-0019).
Copyright © 2019 American Chemical Society.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Materials Chemistry