High charge collection efficiency detector based on plasma purified high-quality diamond

Abstract

Diamond radiation detector is an ideal choice for the next-generation radiation detection in harsh environments, due to its small size, high irradiation resistance and fast response. However, high-purity single crystal diamond is hard to be prepared at the high growth rate due to the inevitable impurity incorporation. In this paper, based on the high-quality high-temperature/high-pressure (HPHT) single crystal diamond substrate, detector-grade single crystal diamonds material with high purity and low defect density were epitaxially grown at growth rate of about 4 μm/h by using plasma environment purification technology. It showed that the full width at half maximum of X-ray rocking curve of high-quality single crystal diamond could reach 0.007°, there was no nitrogen related impurity in PL spectrum, and the substitutional nitrogen content estimated by UV absorption spectrum was less than 10 ppb. After metallization and packaging process, the diamond detectors were prepared and the detector response under irradiation with 241Am α-particles was realized. For the sample with fewer dislocations, the charge collection efficiency and energy resolution of this detector were 86.8 % and 7.85 % for electrons, and 96.7 % and 2.48 % for holes. The product of mobility and lifetime of electrons and holes were 1.7 × 10−4 cm2V−1 and 3.7 × 10−4 cm2V−1, respectively. The high performances of the detector indicate that the current diamond detector can meet the application requirements of commercial diamond detectors.