Cathodoluminescence of silicon doped aluminum nitride with scanning transmission electron microscopy

Matthew R Hauwiller,Timothy B Eldred,James Lebeau,Zlatko Sitar,Seiji Mita,Ramon Collazo,David Stowe

doi:10.1063/5.0019863

Matthew R Hauwiller, Timothy B Eldred + Show 5 more

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https://doi.org/10.1063/5.0019863

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Abstract

Here, we apply cathodoluminescence in scanning transmission electron microscopy to infer the influence of dislocation strain fields on the formation of point defect complexes in Si doped AlN. In addition to identifying non-radiative recombination centers, tracking Si related defect emission energies reveals a red-shift at threading dislocations. We discuss these results in the context of multiple Si-vacancy defect complexes that can form and the influence of local strain on their formation energies. By correlating the electronic and structural properties at the nanoscale, cathodoluminescence elucidates the inhomogeneity of defect complexes in Si doped AlN and offers the potential for strain engineering to control the defect energy formation landscape.

Highlights

Similar to PL, which excites the sample with a source of light and measures the emitted photon spectra, cathodoluminescence (CL) excites carriers in the sample with a source of high energy electrons and the emitted photons are collected via mirrors placed in close proximity to the sample.13,14 When combined with scanning transmission electron microscopy (STEM), which rasters a finely focused electron probe across the sample, CL can explore the luminescent properties of a material with nanometer scale spatial resolution.15 unlike more traditional spectroscopy methods in STEM that require percent-level concentrations, such as electron energy loss or x-ray spectroscopy, CL emission scitation.org/journal/apm spectra can be sensitive up to 1014/cm3, enabling one to probe the electronic structure of defect complexes
We apply cathodoluminescence in scanning transmission electron microscopy to infer the influence of dislocation strain fields on the formation of point defect complexes in Si doped AlN
In addition to identifying non-radiative recombination centers, tracking Si related defect emission energies reveals a red-shift at threading dislocations

Summary

Introduction

Similar to PL, which excites the sample with a source of light and measures the emitted photon spectra, cathodoluminescence (CL) excites carriers in the sample with a source of high energy electrons and the emitted photons are collected via mirrors placed in close proximity to the sample.13,14 When combined with scanning transmission electron microscopy (STEM), which rasters a finely focused electron probe across the sample, CL can explore the luminescent properties of a material with nanometer scale spatial resolution.15 unlike more traditional spectroscopy methods in STEM that require percent-level concentrations, such as electron energy loss or x-ray spectroscopy, CL emission scitation.org/journal/apm spectra can be sensitive up to 1014/cm3, enabling one to probe the electronic structure of defect complexes. We apply cathodoluminescence in scanning transmission electron microscopy to infer the influence of dislocation strain fields on the formation of point defect complexes in Si doped AlN.

Results

Conclusion