Ultrathin Pyrolytic Carbon Films on a Magnetic Substrate

TL;DR

This paper demonstrates the growth of uniform ultrathin pyrolytic carbon films on nickel substrates via chemical vapor deposition, emphasizing the importance of rapid cooling and characterizing crystal size with Raman spectroscopy.

Contribution

It introduces a method for producing uniform PyC films on nickel and provides detailed characterization of their in-plane crystal size using Raman spectroscopy.

Findings

Mean in-plane crystal size of 22.9 nm

Rapid cooling is essential for film uniformity

Raman spectroscopy effectively characterizes crystal size

Abstract

We report the growth of ultrathin pyrolytic carbon (PyC) films on nickel substrate by using chemical vapor deposition at 1000 {\deg}C under methane ambience. We find that the ultra-fast cooling is crucial for PyC film uniformity by controlling the segregation of carbon on nickel. We characterize the in-plane crystal size of PyC film by using Raman spectroscopy. The Raman peaks at ~1354 cm-1 and ~1584 cm-1 wavenumbers are used to extract the D and G bands. The corresponding peak intensities are then used in an excitation energy dependent equation to calculate the in-plane crystal size. Using Raman area mapping, the mean value of in-plane crystal size over an area of 100 {\mu}m ${\times}$ 100 {\mu}m is about 22.9 nm with a standard deviation of about 2.4 nm.