Diamond's many extreme properties, such as its radiation and corrosion resistance, large bandgap, high electron and hole mobility, make it an attractive semiconductor for UV and particle detectors. This paper reviews the properties that are exploited by the latest generation of detectors, such as the radiation hardness and detection mechanisms, and those which are less well understood, such as grain boundaries and priming effects. The UV and particle detectors and dosimeters that have been reported in the last few years are described and briefly assessed.

https://iopscience.iop.org/article/10.1088/0268-1242/15/9/201/pdf

Recent developments of diamond detectors for particles and UV radiation

The thermoluminescent (TL) response of a set of synthetic diamond films obtained by chemical vapour deposition was investigated using gamma and beta radioactive sources over the dose range from 60 mGy to 3.5 Gy. A TL response linear with dose was generally observed. A numerical curve-fitting procedure was applied to deconvolute the complex-structured TL glow curves, which were found to be composed at most by five peaks in the temperature range between C to C. A short preheat treatment after irradiation allowed us to obtain a very stable smooth-shaped glow curve composed of a unique peak close to C. This isolated structure followed first-order kinetics over the whole dose range. The activation energy of the main peak, eV, was determined considering all samples and all irradiation doses using both the peak shape method and the fitting procedure. The corresponding frequency factor was estimated to be within the range -. The TL sensitivity of the diamond films calculated considering the isolated high-temperature peak compares favourably with that measured with a set of LiF TLD100 and TLD700 standard dosimeters.

Thermoluminescence analysis of - and -irradiated chemical vapour deposited diamond films

The effect of ion implantation on thermally stimulated currents in polycrystalline CVD diamond

Growth, characterization and properties of CVD diamond films for applications as radiation detectors

We have studied the morphology and texture of CVD diamond films grown by d.c. plasma glow discharge CVD by means of SEM analysis and X-ray diffraction. This works follows a preliminary work on morphology changes from disordered to textured structure with a thorough investigation in a wide interval of substrate temperature, 955–1150°C, and methane into hydrogen volume concentration, 0.9–3.8%. The other deposition parameters have been kept constant: overall pressure, 210 Torr, gas flow rate 300 sccm, power density, 38 W mm −2 . Care has been taken to prepare the substrate with a standard procedure in order to avoid unreproducible effects on nucleation and growth. In-plane texture has been determined by calculating the average percentage of oriented grains from the area of the Bragg peaks and the powder diffraction data. The results of this quantitative analysis confirm the SEM morphology observation. A fieldmap has been developed for the film morphology and texture as functions of substrate temperature and methane concentration in order to give an useful information for directing the CVD process by means of this particular method. Moreover a qualitative agreement with previously reported data supports the hypothesis that the morphology does not depend on the particular CVD method but only on the deposition conditions, i.e. the deposition parameters and the activation of the reactant gases. The density of nucleation has been also studied by SEM analysis, leading to conclude that there is no competition between grains and evolutionary growth for the used deposition conditions, resulting in grain sizes within the same order of magnitude of the film thicknesses. A clear correlation has been found between the rate of growth of the films and their texture, in the sense that maxima and minima of the rate of growth always correspond to maxima in the diamond texture. A thorough explanation of this correlation will require further ad hoc investigations.

Fieldmap of morphology of diamond films grown by use of d.c. plasma glow discharge chemical vapour deposition

Thermoluminescent properties of three samples of synthetic diamond obtained by chemical vapor deposition (CVD) were investigated. The thermoluminescent response of the three samples was observed increasing linearly with radiation exposure over a wide range of doses (from 60 mGy up to 3 Gy). The measurement of their activation energies and frequency factors are reported. First-order kinetics was observed in the three cases.

/pdf/investigation-of-thermoluminescent-properties-of-synthetic-2ax1xr6ivy.pdf

C. Leroy

Papers

Investigation of thermoluminescent properties of synthetic (CVD) diamond

Defect analysis in beta -irradiated undoped cvd diamond films