Charge transport in single crystal CVD diamond studied at high temperatures

Andreo Crnjac,Milko Jakšić,Michal Pomorski,Mauricio R Ramos,Natko Skukan

doi:10.1088/1361-6463/ac1e4e

Abstract

The capability of single crystal diamonds to maintain their unique electronic properties even at high temperatures is, in particular, relevant for its applications as a radiation detector. In order to explore characteristics of charge transport at high temperatures (up to 450 ∘C), diamond was exposed to MeV energy ions, both, to induce radiation damage and to probe subsequent influence on detector’s properties. Dependence of mobility-lifetime product with temperature has been obtained for electrons and holes. For holes, mu-tau displays a linear degradation with rising temperature, while for electrons, change with temperature is less evident. Furthermore, deep trapping levels induced in the material by radiation damage, were studied through time-resolved charge signals. Detrapping time was extracted from this data. Hole trap level, with the activation energy of 0.53 ± 0.01 eV has been detected in the regions of the diamond detector previously irradiated by 5 MeV damaging proton beam, but not in the pristine regions. This indicates that the trap was formed due to defect induction during radiation damage exposure. Activation of this deep level is important for charge transport performance in diamond detectors operating at high temperatures and high radiation conditions.

Highlights

Employment of diamond for radiation detection, power electronics and optoelectronics has been increasing steadily in the last two decades
In a recent work [15] we have investigated spectroscopic properties of a radiation detector, based on a single crystal CVD diamond, prepared for high-temperature operation
For the study of the thermally stimulated detrapping, we acquired charge transients induced by the ion beam, that was positioned either in the central part of the previously irradiated region, or in the pristine area

Summary

Introduction

Employment of diamond for radiation detection, power electronics and optoelectronics has been increasing steadily in the last two decades. Diamond is an ultra-wide-band-gap semiconductor (5.5 eV) with excellent properties: breakdown voltage >10 MV/cm, high electron and hole mobilities, chemical inertness, radiation hardness, high thermal conductivity [3]. Based on these properties, diamond-based radiation detectors have found increasing use for operation in harsh environments, high radiation and/or high temperature conditions, that can be encountered at nuclear fusion reactors or other nuclear or particle physics experimental facilities [4,5,6]. High thermal conductivity is here especially important for heat dissipation, as it was demonstrated for diamond-based JFET [8] that was able to operate at temperatures up to 450 ◦ C

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Conclusion