Nano-cube MgO formed on silicon substrate using pulsed laser deposition

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Epitaxial growth of magnesium oxide (MgO) on silicon (Si) substrates is crucial for advanced electronic and optical applications.
• Achieving high-quality, continuous MgO films on Si(001) presents challenges due to lattice mismatch and surface interactions.

Purpose of the Study:

• To investigate the formation and structural characteristics of MgO films deposited on Si(001) substrates using pulsed laser deposition.
• To analyze the morphology and phase evolution of MgO nanoparticles under different conditions, including annealing.

Main Methods:

• Pulsed laser deposition (PLD) of an MgO target onto Si(001) substrates at elevated temperatures and controlled oxygen pressures.
• Surface characterization using Atomic Force Microscopy (AFM) to observe morphology.
• Chemical and structural analysis using X-ray Photoelectron Spectroscopy (XPS) and X-ray Diffraction (XRD).

Main Results:

• MgO films exhibited a (001) preferred orientation on Si(001) substrates, indicating cubic-on-cubic epitaxial growth.
• XPS analysis revealed that the deposited MgO did not form a continuous film, but rather scattered nano-cube particles on the Si surface.
• AFM imaging confirmed the presence of nano-cube MgO particles, which transformed into round shapes after annealing.
• XRD confirmed the epitaxial relationship: MgO[100] parallel to Si[100].

Conclusions:

• Pulsed laser deposition can yield epitaxially grown MgO(001) on Si(001) with a cubic-on-cubic arrangement.
• The formation of discrete MgO nanoparticles rather than a continuous film was observed, with shape transformation upon annealing.
• The study provides insights into controlling MgO nanostructures on silicon for potential device applications.