Fabrication of iron carbide by plasma-enhanced atomic layer deposition

摘要

Iron carbide (Fe_(1-x)C_x) thin films were successfully grown by plasma-enhanced atomic layer deposition (PEALD) using bis(N,N'-di-tert-butylacetamidinato)iron(Ⅱ) as a precursor and H_2 plasma as a reactant. Smooth and pure Fe_(1-x)C_x thin films were obtained by the PEALD process in a layer-by-layer film growth fashion, and the x in the nominal formula of Fe_(1-x)C_x is approximately 0.26. For the wide PEALD temperature window from 80 to 210 °C, a saturated film growth rate of 0.04 nm/cycle was achieved. X-ray diffraction and transition electron microscope measurements show that the films grown at deposition temperature 80-170 °C are amorphous; however, at 210 °C, the crystal structure of Fe_7C_3 is formed. The conformality and resistivity of the deposited films have also been studied. At last, the PEALD Fe_(1-x)C_x on carbon cloth shows excellent electrocatalytic performance for hydrogen evolution.