HYDROGEN-INDUCED VIBRATIONAL AND ELECTRONIC-TRANSITIONS IN CHEMICAL-VAPOR-DEPOSITED DIAMOND, IDENTIFIED BY ISOTOPIC-SUBSTITUTION

Homoepitaxial diamond films grown by chemical vapor deposition from 12C and 13C containing gases have been studied by Fourier transform infrared spectroscopy. A sharp absorption band observed at 3123 cm-1 is attributed to a CH vibrational absorption. It resembles the previously observed 3107 cm-1 absorption band in natural diamond. Isotopic replacement of carbon, hydrogen, and nitrogen by 13C, 2H, and 15N reveals, that a CH center without nitrogen participation is responsible for this new absorption. Furthermore, new hydrogen related electronic transitions have been observed around 7300 cm-1. These lines shift to higher energies in 13C crystals, in accordance with the increase of the electronic band gap. © 1995 American Institute of Physics.