Design, fabrication and testing of CVD diamond detectors with high performance

Abstract

A single crystal diamond (SCD) detector and a polycrystalline diamond (PCD) detector have been designed and fabricated using electronic grade CVD diamond. The fabricated detectors were tested for their dark current and X-ray photocurrent. It was found that the SCD and PCD detectors have superb signal to noise ratios (SNR) under X-ray irradiation from an Ag target with 10kV and 40kV accelerating voltage, 2000 and 7000 respectively for the SCD detector and 550 and 2000 for the PCD detector. The performance of these detectors using an 241Am α source was tested under different bias voltages and the results were benchmarked against a commercial SCD detector. The typical rise time of an α event in both of the fabricated detectors are about 1.2ns. The fabricated SCD detector has a 3.7% net energy resolution while that of the commercial detector is about 3.9%. The pulse height spectra are integrated and fitted to obtain the charge collection efficiency. For the fabricated SCD detector, this value is above 97% at bias 200V or beyond, which is 1-2% higher than that of the commercial detector at the same voltage. Finally, the fabricated PCD detector can also detect the presence of α particle although it only has a continuous and decreasing energy spectrum under α radiation. These results fully reveal that the fabricated SCD detector has good performance as a multifunctional detector for both X-ray and α radiation, and show great potential as neutron spectrometer as well.

Comparative study of Single Crystal (SC)-Diamond and 4H-SiC bulk radiation detectors for room temperature alpha spectroscopy

“…It is to be noted that the leakage current density is nearly symmetrical in both directions of the applied electric field, thus reconciling the dominance of bulk conduction over other conduction mechanisms leading to nearly ohmic nature of the deposited contacts. The leakage current density of the SC-diamond detector is consistent with the studies carried out by Liu et al [22] and Tsubota et al [23]. The 𝐶-𝑉 characteristics for ±30 V for the SC-diamond detector is reported by the same authors elsewhere [19].…”

“…In summary, although HPSI-SiC has the high resistivity required for radiation detection, the charge collection properties and hence the spectral resolution of HPSI SiC detectors of equivalent thickness is poor compared to the diamond detectors. In addition to lower 𝜇𝜏 product and CCE, The time-stability of SC-diamond detectors under constant alpha irradiation is an important issue owing to their prolonged use in tokamaks [22]. One of the advantages of SC-diamond over other semiconductor radiation detectors viz.…”

Rational design of diamond through microstructure engineering: From synthesis to applications

“…202 The rough surface of PCD poses challenges in achieving high-resolution contacts, and the relatively high concentration of GBs can restrict carrier transport, affecting the detector performance. Liu et al 195 found that reducing the electrode spacing to a size comparable to the grain size improves the detector performance by mitigating the GB effect. According to the published results, the photoelectrical properties of small-grain CVD diamond are controlled by the amorphous-carbon-lie density of states existed at the GBs.…”

“…(E) Dark current and photocurrent of the SCD and PCD detectors. Reproduced under the terms of the CC‐BY license: Copyright 2019, Authors, published by AIP Publishing 195 …”

XMEA: A New Hybrid Diamond Multielectrode Array for the In Situ Assessment of the Radiation Dose Enhancement by Nanoparticles

“…Due to its physical and chemical properties, diamond is considered an excellent material for the detection of high-energy photons, ranging from deep-UV to X- and gamma rays. Several groups worldwide developed diamond X-ray detectors and dosimeters, both on single crystals and on polycrystalline diamond [ 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. Diamond detectors have been used to quantify the radiation dose in external beam radiation therapy using X-rays and particle beams [ 37 , 38 , 39 ].…”