Atomic layer deposition of metal phosphates

Abstract

Because of their unique structural, chemical, optical and biological properties, metal phosphate coatings are highly versatile for various applications. Thermodynamically facile and favorable functionalization of phosphate moieties (like orthophosphates, metaphosphates, pyrophosphates, phosphorus-doped oxides...) make them highly sought-after functional materials as well. Being a sequential self-limiting technique, atomic layer deposition has been used for producing high quality conformal coatings with sub-nanometer control. In this review, different atomic layer deposition based strategies used for the deposition of phosphate materials are discussed. The mechanisms underlying those strategies are discussed, highlighting advantages and limitations of specific process chemistries. In a second part, the application of metal phosphates deposited through atomic layer deposition in energy storage and other emerging technologies such as electrocatalysis, biomedical or luminescence applications are summarized. Next to this, perspectives on untangled knowledge gaps and opportunities for future research are also emphasized.1

Atomic Layer Deposition—A Versatile Toolbox for Designing/Engineering Electrodes for Advanced Supercapacitors

“…The deposition rate in an ALD process is governed by the used precursors, reaction temperatures, as well as the target substrate, and its typical values range within a few angstroms (generally < 2 Å per cycle). [123,134,135,145,146,157,[170][171][172][173][174] In addition to the control of deposition rates, ALD offers excellent control over the stoichiometry of the deposited material. In this perspective, the stoichiometry of ALD-grown layers almost corresponds to the theoretical The intense nature of the ALD procedure predictions; however, the reaction temperatures along with the precursor materials can affect the resulting films.…”

“…In contrast, a conformal film contains an identical thickness inside the 3D structures, i.e., an “around‐the‐corner” uniformity. [ 173 ] However, to achieve highly conformal films inside/outside the multifaceted constructions, numerous aspects should be considered, such as sticking probability, surface diffusion, and precursor flux. Thus, the reactants should permit chemisorption over the entire substrate surface.…”

Atomic layer deposition for tuning the surface chemical composition of nickel iron phosphates for oxygen evolution reaction in alkaline electrolyzers

“…ALD is a thin film deposition method known for its superior uniformity and conformality on complex 3D substrates. A wide variety of ALD process chemistries is available that yield phosphate materials with different phosphorous content, ranging from P-rich to P-doped materials [21,22]. ALD-grown phosphates have found applications in Li-ion battery electrode design [21], while a few works have studied amorphous cobalt phosphates for OER catalysis [6,15,22,23].…”

Depositing ALD-oxides on MLD-metalcones: enhancing initial growth through O2 plasma densification

“…Since its discovery, Atomic Layer Deposition (ALD) has been used for an increasingly broader range of applications and, nowadays, ALD coatings are among us in areas like semiconductors, 1 batteries 2 or biomedical devices, 3 just to name a few.…”