Modified 241Am-Be neutron beams showed an ability to change the optical properties of zinc oxide (ZnO) photoluminescence (PL) spectra by transmuting zinc (Zn) into gallium (Ga) after irradiation. This study investigates the time required by slow neutron irradiation to register the transmutation of the Zn into Ga. Two series of samples from different suppliers hydrothermally (HT) grown by TEW Tokyo Denpa Co. Ltd., Tokyo, Japan, and MTI corporation, China, are irradiated for 6, 12, 18, and 24 days on the Zn-polar face of each sample to specify the relationship between the irradiation intensity and transmutation.

This study investigates the effect of neutron irradiation on zinc oxide (ZnO) crystal bulk substrates that have been ion-implanted with gadolinium (Gd) and iron (Fe) in different concentrations in the Zn-polar (0001) face of the crystal to produce Gd:ZnO and Fe:ZnO crystal bulk samples. The neutron beams of the 241Am–Be flux were moderated to be 7 × 104 n/s cm2 by a 4.5 cm-thick wax. The implanted face was left to face the neutron beams on top of the wax for 90 h. The results show that the nuclear reaction between thermal neutrons and the implanted material produced a large amount of heat, which significantly enhanced the photoluminescence spectra of the crystal bulk surface after the surface damage caused by ion implantation. This study provides insights into the benefits of having a doped material in the ZnO crystal after irradiation and highlights the potential of neutron irradiation as a method for enhancing the properties of implanted crystal bulk substrates.