Tailoring the Electronic Structures and Spectral Properties of ZnO with Irradiation Defects Generated Under Intense Electronic Excitation: A Combined Experimental and DFT Approach

Xinqing Han, Runhan Li, Shangfa Pan, Yong Liu, Chengwang Niu, Miguel L. Crespillo, Eva Zarkadoula, Peng Liu

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

The relationship between the composition of the internal defect states, spectral properties, and correlated electronic structures of wurtzite zinc oxide (ZnO) crystals under 645 MeV Xe35+ irradiation is systematically investigated, employing experimental characterizations combined with first-principle 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.

Original languageEnglish
Article number2405885
JournalAdvanced Functional Materials
Volume34
Issue number42
DOIs
StatePublished - Oct 15 2024

Funding

This research was funded by the National Key Research and Development Program of China (No. 2022YFE0124200), the National Natural Science Foundation of China (No. 12322514), the China Postdoctoral Science Foundation (No. 2023TQ0186, 2023M742062), the Postdoctoral Fellowship Program of CPSF (No. GZC20231440), and the National Laboratory of Heavy Ion Accelerator in Lanzhou. E.Z. was supported by the Center for Nanophase Materials Sciences, (CNMS), which is a US Department of Energy, Office of Science User Facility at Oak Ridge National Laboratory.

Keywords

  • density functional theory
  • electronic structures
  • intense electronic excitation
  • microstructure formation
  • spectral decomposition

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