The sensitive determination of H in diamond by infrared (FTIR) spectroscopy and micro-elastic-recoil (mu-ERDA) techniques

A Delta E-E telescope was used in coincidence to analyse diamond samples by recoil of hydrogen (ERDA) using 4.1 MeV He+. Comparison of the results fro m silicates with known PT-abundances suggested sensitivities of <50 atomic ppm. A slice of type Ib diamond was prepared and implanted with known amoun ts of hydrogen (1000, 150, 40 and 10 atomic ppm). The analysis of this manu factured standard by ERDA showed that the 1000 and 150 ppm implants were re solvable. The presence of intrinsic hydrogen in the diamond prevented resol ution of the lower H implants. A number of diamonds from southern Africa we re analysed for their PT-content using ERDA and Fourier transform infrared (FTIR) techniques. There was no correlation between the results of both tec hniques. It was concluded that much of the hydrogen in diamond (typically 1 00-4000 atomic ppm in the specimens analysed) was not infrared active (i.e. not bonded to C or N in the diamond lattice). (C) 1999 Elsevier Science B. V. All rights reserved.