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Defect-Selective Luminescence in Hydroxyapatite Under Electron and Gallium Ion Beams
Verónica J Huerta1, Fabián Martínez2, Hanna M Ochoa1
1Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Ensenada C.P. 22800, Baja California, Mexico.
Materials (Basel, Switzerland)
|January 28, 2026
Summary
Electron and ion irradiation selectively alter luminescence in calcium-deficient hydroxyapatite (HAp). This defect engineering approach offers new possibilities for tailoring HAp
Area of Science:
- Materials Science
- Solid State Physics
- Luminescence Spectroscopy
Background:
- Hydroxyapatite (HAp) is a crucial biomaterial with optical properties influenced by defects.
- Understanding defect-luminescence relationships is key to optimizing HAp applications.
- Irradiation is a potential method for controlled modification of HAp properties.
Purpose of the Study:
- To investigate the defect-selective luminescence response of calcium-deficient hydroxyapatite (HAp) under electron and ion irradiation.
- To analyze the impact of irradiation on defect-related luminescence using photoluminescence (PL) and cathodoluminescence (CL) techniques.
- To explore irradiation as a tool for defect engineering in HAp.
Main Methods:
- Preparation of compacted HAp pellets from hydrothermally grown nanofibers.
- Photoluminescence (PL) and Cathodoluminescence (CL) spectroscopy before and after irradiation.
- Low-energy electron beam irradiation (15 keV) and Ga+ ion irradiation (30 keV).
- Monochromatic transient CL measurements to analyze luminescence decay dynamics.
Main Results:
- Electron irradiation induced a two-stage luminescence response: initial enhancement of OH-related bands (2.57, 2.95 eV) due to vacancy activation, followed by decay from annealing.
- Ion irradiation led to monotonic luminescence quenching, primarily by annealing oxygen vacancies in PO43- groups.
- Decay constants indicated faster annealing of activated OH-channel vacancies compared to other defect centers.
- Irradiation demonstrated selective control over different luminescence bands in HAp.
Conclusions:
- Irradiation acts as a versatile tool for defect engineering in hydroxyapatite, enabling selective modification of luminescence.
- Electron-induced activation and ion-driven suppression provide complementary pathways for defect control.
- These findings offer fundamental insights into vacancy stability and open avenues for tailoring HAp's optical, sensing, and bioimaging functionalities.
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