# VN Thin Films via MOCVD Using a New Vanadium Precursor: Linking Growth Chemistry to Functional Surface Properties

## TL;DR

A new vanadium precursor enables precise growth of crystalline vanadium nitride thin films, which could improve electrochemical nitrogen reduction.

## Contribution

A new MOCVD process using a vanadium precursor and NH3 enables controlled growth of VN thin films for eNRR applications.

## Key findings

- N,N’-diisopropylformamidinatovanadate is a suitable MOCVD precursor for VN thin films.
- NH3 influences decomposition pathways and film properties, confirmed by DFT simulations.
- VN films on Ti substrates show potential for electrochemical nitrogen reduction.

## Abstract

Vanadium nitride (VN) is a promising material for many applications, including the electrochemical nitrogen reduction reaction (eNRR). Catalyst nanoengineering enables experimental validation of its predicted eNRR activity, but most VN catalysts are made by using methods that lack precise control. This study introduces a new metalorganic chemical vapor deposition (MOCVD) process for high‐quality, faceted, and crystalline VN thin films. N,N’‐diisopropylformamidinatovanadate [V(dpfamd)3] is identified as a suitable precursor with favorable thermal properties. Using NH3 as a co‐reactant yields pure crystalline VN thin films on Si substrates. To investigate structure–property relationships relevant to eNRR, the films are characterized by X‐ray diffraction (XRD), Rutherford backscattering spectrometry combined with nuclear reaction analysis (RBS/NRA), X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Observing NH3’s strong influence during growth, first principles density functional theory (DFT) simulations are performed, supporting an energetically favorable decomposition pathway of [V(dpfamd)3] to VN with NH3 present. Process transfer from Si to conductive Ti substrates, required for in‐depth electrochemical testing, yields VN thin‐film properties similar to those on Si. Preliminary eNRR measurements indicate a potential correlation between faceting and eNRR activity, highlighting the potential of MOCVD‐grown VN thin films for future eNRR applications.

A new vanadium precursor enables metalorganic chemical vapor deposition growth of pure and crystalline VN thin films with tailored orientation. Combined experiments and density functional theory calculations reveal the crucial role of NH3 in controlling decomposition pathways and film characteristics. Transferring the process to conductive Ti substrates reveals VN as a promising candidate for nanoengineered electrocatalysts in sustainable nitrogen reduction.