Abstract

Electron irradiation of hexagonal boron nitride (hBN) in a transmission electron microscope is shown to produce circular pores in ultra-high vacuum, whereas small amounts of oxygen in the microscope column drive pore growth into triangular shapes with nitrogen-terminated edges. The effect is observed across hBN samples from different sources, under different electron energies, and for focused as well as defocused beams. Experiments and DFT calculations indicate that oxygen radicals are responsible for the chemical contribution to pore growth and edge termination.

Abstract

Electron irradiation of hexagonal boron nitride (hBN) in a transmission electron microscope is shown to produce circular pores in ultra-high vacuum, whereas small amounts of oxygen in the microscope column drive pore growth into triangular shapes with nitrogen-terminated edges. The effect is observed across hBN samples from different sources, under different electron energies, and for focused as well as defocused beams. Experiments and DFT calculations indicate that oxygen radicals are responsible for the chemical contribution to pore growth and edge termination.

Abstract

Electron irradiation of hexagonal boron nitride (hBN) in a transmission electron microscope is shown to produce circular pores in ultra-high vacuum, whereas small amounts of oxygen in the microscope column drive pore growth into triangular shapes with nitrogen-terminated edges. The effect is observed across hBN samples from different sources, under different electron energies, and for focused as well as defocused beams. Experiments and DFT calculations indicate that oxygen radicals are responsible for the chemical contribution to pore growth and edge termination.

Abstract

Electron irradiation of hexagonal boron nitride (hBN) in a transmission electron microscope is shown to produce circular pores in ultra-high vacuum, whereas small amounts of oxygen in the microscope column drive pore growth into triangular shapes with nitrogen-terminated edges. The effect is observed across hBN samples from different sources, under different electron energies, and for focused as well as defocused beams. Experiments and DFT calculations indicate that oxygen radicals are responsible for the chemical contribution to pore growth and edge termination.