Characterization of Fe-N nano crystals and nitrogen-containing inclusions in (Ga,Fe)N thin films using transmission electron microscopy

TL;DR

This study uses advanced electron microscopy techniques to analyze nitrogen-containing inclusions and Fe-N nanocrystals in (Ga,Fe)N thin films, revealing their structure, nitrogen content, and formation process.

Contribution

It provides detailed characterization of nitrogen inclusions and nanocrystals in (Ga,Fe)N films, elucidating their structure and nitrogen content with in situ experiments.

Findings

Nitrogen inclusions are adjacent to Fe-N nanocrystals in (Ga,Fe)N.

High nitrogen density measured in inclusions (~1.4 g/cm3).

Nanocrystals are truncated at inclusion boundaries, indicating interaction.

Abstract

Nanometric inclusions filled with nitrogen, located adjacent to FenN (n = 3 or 4) nanocrystals within (Ga,Fe)N layers, are identified and characterized using scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS). High-resolution STEM images reveal a truncation of the Fe-N nanocrystals at their boundaries with the nitrogen-containing inclusion. A controlled electron beam hole drilling experiment is used to release nitrogen gas from an inclusion in situ in the electron microscope. The density of nitrogen in an individual inclusion is measured to be 1.4 +- 0.3 g/cm3. These observations provide an explanation for the location of surplus nitrogen in the (Ga,Fe)N layers, which is liberated by the nucleation of FenN (n> 1) nanocrystals during growth.