Controlling Atomic Layer Deposition of 2D Semiconductor SnS2 by the Choice of Substrate

• Published in: Advanced materials interfaces Vol. 7; no. 19
• Main Authors: Mattinen, Miika, King, Peter J., Brüner, Philipp, Leskelä, Markku, Ritala, Mikko
• Format: Journal Article
• Language: English
• Published: Weinheim John Wiley & Sons, Inc 01.10.2020
• Subjects: 2D materials; Aluminum oxide; atomic layer deposition; Atomic layer epitaxy; Epitaxial growth; Film thickness; Ion scattering; Materials selection; Mica; Monolayers; Multilayers; Muscovite; Optoelectronics; Sapphire; semiconductors, SnS 2; Silicon dioxide; Silicon substrates; Tin disulfide; Titanium dioxide; Two dimensional materials
• ISSN: 2196-7350; 2196-7350
• DOI: 10.1002/admi.202001046

Semiconducting 2D materials, such as SnS2, hold great promise in a variety of applications including electronics, optoelectronics, and catalysis. However, their use is hindered by the scarcity of deposition methods offering necessary levels of thickness control and large‐area uniformity. Herein, a low‐temperature atomic layer deposition (ALD) process is used to synthesize up to 5 × 5 cm2 continuous, few‐layer SnS2 films on a variety of substrates, including SiO2/Si, Si‐H, different ALD‐grown films (Al2O3, TiO2, and Ir), sapphire, and muscovite mica. As a part of comprehensive film characterization, the use of low energy ion scattering (LEIS) is showcased to determine film continuity, coverage of monolayer and multilayer areas, and film thickness. It is found that on sapphire substrate, continuous films are achieved at lower thicknesses compared to the other substrates, down to two monolayers or even less. On muscovite mica, van der Waals epitaxial growth is realized after the post‐deposition annealing, or even in the as‐deposited films when the growth is performed at 175 to 200 °C. This work highlights the importance of the substrate choice for 2D materials and presents a practical low‐temperature method for the deposition of high‐quality SnS2 films that may be further evaluated for a range of applications. The crucial role of substrate in controlling atomic layer deposition of 2D semiconductor SnS2 films is studied. SnS2 films deposited on different substrates under mild conditions exhibit differences in continuity, morphology, and crystallinity. In particular, ultrathin continuous SnS2 films can be deposited on sapphire. On muscovite mica, the films grow in van der Waals epitaxial manner.