Crystallize it before it diffuses: Thin -film growth of the phosphorus-rich semiconductor CuP2
Feng Yi, David A. LaVan, Andrea Crovetto, Danny Kojda, Karen Heinselman, Klaus Habicht, Thomas Unold, Andriy Zakutayev
Numerous phosphorus-rich metal phosphides containing both P-P bonds and metal-P bonds are known from the solid state chemistry literature. Yet, very little is known about the thin- film synthesizability and properties of even the simplest binary compounds in this family. In this work, we demonstrate growth of single-phase CuP2 films by a two-step process involving reactive sputtering of amorphous CuP2+x and rapid annealing in an inert atmosphere. At the temperature required for crystallization, CuP2 tends to decompose into Cu3P and gaseous phosphorus. However, CuP2 can still be synthesized if the amorphous precursors are mixed on the atomic scale and are sufficiently close to the desired composition (neither too P poor nor too P rich). Fast formation of polycrystalline CuP2, combined with a short annealing time, makes it possible to bypass the diffusion processes responsible for decomposition. Thin- film CuP2 is a semiconductor with a 1:5 eV band gap and interesting properties such as strong optical absorption, low thermal conductivity, and composition-insensitive electrical conductivity. We anticipate that our proposed processing route can be extended to other phosphorus-rich phosphides that are still awaiting thin-film synthesis and could facilitate their high-throughput characterization.
, LaVan, D.
, Crovetto, A.
, Kojda, D.
, Heinselman, K.
, Habicht, K.
, Unold, T.
and Zakutayev, A.
Crystallize it before it diffuses: Thin -film growth of the phosphorus-rich semiconductor CuP2, Journal of American Chemical Society, [online], https://doi.org/10.1021/jacs.2c04868, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=934523
(Accessed February 26, 2024)