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In this study, vertical-type thick BGaN PIN diodes were successfully fabricated to improve the neutron capture rate of BGaN diodes by improving the BGaN epitaxial growth technique. In this technique, 5-μm-thick epitaxial growth was achieved using trimethylboron as a B metal-organic source, which suppressed the gas-phase reaction. The α-particle energy spectrum, the neutron pulse signal, and the residual energy of particles emitted from a neutron capture reaction were measured using the fabricated BGaN diodes by performing radiation detection measurements. The detected signal position in the neutron detection signal spectrum was similar to that of 2.3 MeV α-particles. These results indicate that vertical-type BGaN diodes can be used as effective neutron detectors.

Cadmium telluride (CdTe) is a promising material for semiconductor-based roomtemperature radiation detectors because of its wide bandgap and relatively good carrier transport properties. One remaining issue of CdTe detectors is an instability arising in longterm operation. This instability, called polarization, is explained by charge accumulation due to carrier trapping/detrapping at deep defect levels. However, previous explanations did not include carrier transport in CdTe. In this study, we have investigated carrier transport properties by measuring the carrier transit time at each stage of polarization. As a result, we have developed a polarization model including carrier transport and calculated the electric field distribution across the CdTe detector during polarization.

Herein, a radiation detector made of polycrystalline diamond with a boron (B)‐doped neutron converter layer is presented. The detector is fabricated by the hot filament chemical vapor deposition technique, and consists of an undoped free‐standing polycrystalline diamond layer and a B‐doped polycrystalline diamond top layer that serves as an electrical contact and a converter for neutron‐alpha conversion. Characterization of the diamond films and detector operation is presented. The results indicate that the B‐doped layer acts as an effective neutron‐alpha converter, whereby neutron detection is demonstrated in particle‐counting mode using a multichannel analyzer.

Diamond Radiation Detector Neutron, a promising probe for bioimaging and non‐destructive inspection, demands high efficiency flat‐panel detector for imaging applications. Polycrystalline diamond is a material of choice, with built‐in neutron converter formed by boron doping and scalability to wide‐area image sensor. More information can be found in article number http://doi.wiley.com/10.1002/pssa.202100315 by Tomoaki Masuzawa and co‐workers.