Surface ferromagnetic p-type ZnO nanowires through charge transfer doping

Area of Science:

• Materials Science
• Surface Science
• Condensed Matter Physics

Background:

• Zinc oxide (ZnO) is a versatile semiconductor with applications in electronics and spintronics.
• Controlling the surface properties of ZnO nanostructures is crucial for tailoring their electronic behavior.
• Achieving stable p-type doping in ZnO remains a significant challenge.

Purpose of the Study:

• To investigate the theoretical mechanism of p-type charge transfer doping in ZnO nanowires via molecular adsorption.
• To explore the impact of fluorine molecule adsorption on ZnO surface states and electronic properties.
• To assess the potential for surface ferromagnetism and its stability.

Main Methods:

• First-principles theoretical calculations were employed.
• The study focused on the dissociative adsorption of fluorine molecules on ZnO nanowire surfaces.
• Analysis included surface state occupation, Fermi level alignment, and spin polarization.

Main Results:

• Spontaneous dissociative adsorption of fluorine molecules leads to half-emptying of oxygen-derived surface states.
• This results in the surface Fermi level aligning near the valence band maximum, inducing significant p-type doping.
• The half-filled surface states exhibit full spin polarization, leading to stable room-temperature ferromagnetism.
• Kinetic control of surface transfer doping can result in non-equilibrium steady states.

Conclusions:

• Post-growth engineering of ZnO surface states by molecular adsorption is a viable strategy for achieving p-type doping.
• The observed surface ferromagnetism opens avenues for spintronic applications.
• This approach provides a pathway for manipulating ZnO nanostructures for advanced electronic and spintronic devices.