Thermoluminescence assessment of 0.5, 1.0 and 4.0 μm thick HFCVD undoped diamond films

Chemical vapor deposition (CVD) diamond has not found extensive application as a thermoluminescence (TL) dosimeter, mainly because its TL glow curve shape is not reproducible. A slight variation in the growing conditions may result in strong changes in the morphology, microstructure, and surfaceimpurity-related defects, considerably affecting the TL glow curve features. In order to study the main TL characteristics under controlled growing conditions, we present results on three 0.5, 1.0, and 4.0μmthick hot filamentCVD(HFCVD) diamond films grownon Si (100) substrates. The recordedTLglowcurves were resolved into individual peaks by a home-made deconvolution program and the kinetic parameters of the peaks were extracted. The best fits of the TL glow curves were obtained using four peaks, except for the 4.0 μm thick sample that required five TL components. All samples showed three high intensityTLpeaks between 180-400 °C and a less intense one or two peaks in the 100-180 °C low-temperature region. The lowtemperature components all obey second-order kinetics while the high-temperature ones obey first and 1.6 order kinetics. The samples showed similar TL peaks with comparable kinetics parameters. It is concluded that the manufacturing of high quality HFCVD diamond may require a further improvement in the growing process in order to exploit its excellent tissueequivalence properties in clinical and medical applications. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.