Material preparation / Thin film growth

The preparation of materials in thin film form not only is of technological importance for device applications but also grants access to study and understand the physical properties (magnetic, optical, electronic, acoustic) of materials approaching the two-dimensional limit. One interesting example thereof, which is relevant for this handbook, is the occurrence of long-range magnetic order in two dimensions, initially ruled out by theory (Hohenberg, Phys Rev 158:383–386, 1967; Mermin, Wagner, Phys Rev Lett 17:1133–1136, 1966) but later thoroughly revisited as the advances in thin film growth enabled the preparation of suitable experimental testbeds (Vaz, Bland, Lauhoff, Reports Prog Phys 71:056501, 2008). Now that even the growth of innately 2D materials has been recently achieved by ultrahigh vacuum methods (Chen et al, Science 366:983–987, 2019; Liu et al, npj 2D Mater Appl 1:1–6, 2017; Bedoya-Pinto et al, Intrinsic 2DXY ferromagnetism in a van der Waals monolayer. arXiv:2006.07605), the key mechanisms to stabilize magnetic order in two dimensions have been finally established. The current level of understanding in such a fundamental, long-debated topic would have been not possible without the successful growth and characterization of atomically thin films on a variety of surfaces, using the appropriate methods for a high-quality bottom-up material synthesis.In this chapter, we will briefly describe the most important methods for thin film growth, such as molecular beam epitaxy (MBE), pulsed-laser deposition (PLD), as well as magnetron and ion-beam sputtering. We will start with an introductory section which is common to these vapor phase methods such as the growth modes, the importance of substrate preparation, and the role of buffer layers (Sect. 1.) and then describe the characteristic features of each deposition technique, highlighting practical aspects from the user point of view and including some representative examples of thin film compounds grown with these methods (Sects. 2, 3, 4, and 5)