Carbon K edge spectroscopy of internal interface and defect states of chemical vapor deposited diamond films

Abstract

We have made carbon K edge reflectivity and absorption measurements using synchrotron radiation on diamond crystals and chemical vapor deposited diamond films to determine their electronic structures. Our spectra of diamond films show that both sp² and sp³ bonded carbon atoms are formed during initial nucleation and growth. Transmission spectra of a diamond film with 30 nm diameter cystallites show striking features below the carbon sp³ K edge due to internal interface states and/or defects. We compare these absorption features to x‐ray absorption spectra of clean diamond (111) surface, graphite, and hydrocarbon gases to understand surface chemistry involved in the deposition process.