Doublet Separations #

Ga 2p = 27 eV

Ga 3d = 0.45 eV

Ga 3p = 3.4 eV

Common Overlaps for Ga 2p #

La 3p– Eu 3d – Ba 3p – Xe 3s – Fr 4s – Ag MNN (Al Ka X-rays) – Cd LMM (Al Ka X-rays) – N KLL (Al Ka X-rays)

Auger Energies #

Note – these are listed in KINETIC ENERGY

Ga LMM ≈ 420 eV

Common Binding Energies – Ga 2p #

Common Binding Energies – Ga 3d #

Theory and Background #

Neither the 2p, nor the 3d display any particularly unusual behaviour by XPS.

Experimental Advice #

Gallium XPS analysis may be obtained via either the 2p or 3d regions, primarily. The 3d region may possibly provide an additional insight into the chemical speciation involved, while the 2p region is more intense and suffers fewer overlapping peaks.

Ga 3d, and Ga 2p have markedly different kinetic energies, and hence may be used to extract spatial information from a non-homogeneous sample. The 3p is also available as a relatively useful region, at higher binding energy than the 3d, and hence with fewer overlaps.

The Ga 3d region may overlap with O 2s, In 4d, S 3s, P 3s, Ba 5p, K 3p and La 5p. The Ga 2p region may overlap with the N KLL auger and while the La 3p_3/2 peak may intersect the Ga 2p_3/2 and 2p_1/2, the energy differences and large doublet separation of Ga 2p (26.9 eV) result in a relatively trivial deconvolution.

Data Analysis Guidance #

Care should be taken when considering Ga in layered materials, since the two orbitals (2p vs 3d) will have markedly different IMFP (due to different kinetic energies), and so will have different information depths. You can use this to your advantage however, and extract depth information from a single spectrum.

Obtaining the Ga LMM, and constructing a Wagner plot may aid in chemical identification for Ga compounds.[1]

Reference Datasets #

Coming soon

References #