Recently, Prof. Liu Peng's research group at the Institute of Frontier and Interdisciplinary Science of Shandong University and the Key Laboratory of Particle Physics and Particle Irradiation has made research progress in the field of irradiation effect and technical application. By utilising the Heavy Ion Research Facility in Lanzhou (HIRFL), the correlation between the electronic structure and spectral characteristics of the irradiation microregion was constructed, promoting the understanding of the basic mechanism of irradiation and the interdisciplinary integration of irradiation technology. The research results with the title "Tailoring the Electronic Structures and Spectral Properties of ZnO with Irradiation Defects Generated Under Intense Electronic Excitation: A Combined Experimental and DFT Approach" were published in the Journal of Advanced Functional Materials (IF=19.0). Han Xinqing, a specially supported postdoctoral fellowship, is the first author of the paper, and Eva Zarkadoula, a researcher at Oak Ridge National Laboratory, Prof. Miguel L. Crespillo of the University of Tennessee, Prof. Chengwang Niu, and Prof. Liu Peng of Shandong University are the co-corresponding authors of the paper, and Shandong University is the first unit of completion.

The relationship between the composition of the internal defect states, spectral properties, and correlated electronic structures of wurtzite ZnO crystals under 645 MeV Xe³⁵⁺ irradiation is systematically investigated, employing experimental characterizations combined with first-principles calculations. Based on the ion irradiation-induced thermal expansion and relaxation processes, the high concentration of vacancy/interstitial defects produced from the transient disordered phase in molten track states trigger photoelectric changes, as follows: (i) the generation of internal defect states effectively reduces the intrinsic bandgap (3.25 eV→2.66 eV); (ii) a large number of defective active sites inhibits the recombination between electron-hole pairs, causing dark conductance and photoconductance to increase with increasing damage levels until optimal fluence is achieved. Based on the density functional theory (DFT) with the GGA+U (GGA = generalized gradient approximation) method, the defective models associated with the different electronic structures, density of states, formation energy, and the nature of the chemical bonding are established. The narrowing of the bandgap observed experimentally and the enhancement of carrier concentration originating from the internal electron defect states are qualitatively verified, therefore laying the foundation for designing future nanoscale photoelectronic devices and microelectronics applications.

Prof. Liu Peng's research group focuses on the physical mechanism of ion irradiation and explores the cross-application of irradiation technology in multidisciplinary fields, and his recent work has been published in Adv. Funct. Mater. (2024, 2023), Angew. Chem. (2023), Adv. Energy Mater. (2023), Acta Mater. (2023), etc. This research work was supported by the National Natural Science Foundation of China, the National Key Research and Development Program of China and a special grant from the China Postdoctoral Science Foundation.