Oxidizing Hexagonal Boron Nitride into Fluorescent Structures by Photodissociated Directional Oxygen Radical

Area of Science:

• Materials Science
• Nanotechnology
• Photonics

Background:

• Hexagonal boron nitride (hBN) is a wide band gap semiconductor with potential in photonics.
• Existing methods for hBN modification often involve solvothermal/hydrothermal processes, limiting dry oxidation.
• The chemical stability of hBN presents a challenge for creating fluorescent structures.

Purpose of the Study:

• To report a novel method for the dry oxidation of multilayer hBN into fluorescent structures.
• To investigate the conversion of hBN into boron nitride oxide (BNO) using specific oxidation conditions.
• To achieve bright and photostable photoluminescence from modified hBN.

Main Methods:

• Oxidation of multilayer hBN using ultraviolet (UV) light (λ = 172 nm) to generate oxygen radicals [O(³P)].
• Utilizing a gradient magnetic field to direct the paramagnetic oxygen radicals towards the hBN.
• Characterization of the resulting boron nitride oxide (BNO) micro/nanostructures, including BO, BO₂, and O-doped hBN.

Main Results:

• Successful dry oxidation of hBN into fluorescent BNO micro/nanostructures.
• Formation of BNO structures composed of BO, BO₂, and O-doped hBN.
• Achieved bright and photostable wide-band photoluminescence in oxidized BNO with nanosecond-scaled lifetimes.

Conclusions:

• The UV-induced oxidation in a gradient magnetic field is an effective method for modifying hBN.
• The resulting BNO exhibits promising photoluminescent properties for photonic applications.
• This technique overcomes the challenge of dry oxidation for chemically stable hBN.