XPS
Specialist : Dr. Burcu Selen ÇAĞLAYAN
Phone : +90 212 359 68 56, 359 48 06
Fax : +90 212 358 27 24
E-mail : selenbur@boun.edu.tr
X-ray photoelectron spectroscopy (XPS) is a quantitative analysis technique of the surface composition, which is capable of providing atomic and molecular information regarding the surface of the material. It is used to examine core-levels and subsequently to study the composition and electrostatic states of the surface region of a sample by energy-disperse analysis of the emitted core photoelectrons.
Using XPS, some important questions can be answered.
· Which elements are present at the surface?
· What chemical states of these elements are present?
· How much of each chemical state of each element is present?
· What is the spatial distribution of the materials in three dimensions?
· If material is present as a thin film at the surface,
o How thick is the film?
o How uniform is the thickness?
o How uniform is the chemical composition of the film?
XPS is used widely in all branches of pure and applied sciences- as well as for troubleshooting and quality assurance purposes- but some main headings are given here.
· Microanalysis of the surfaces of metals and alloys
· Study of mineral surfaces
· Study of polymers
· Study of materials used for medical purpose
· Surface study of cements and concretes
· Study of basic atomic physics
In our laboratory at Bogazici University Advanced Technologies R&D Center, Thermo Scientific K-Alpha X-ray Photoelectron Spectrometer is used.
Key Features
· Analyzer
o 180° double focusing hemispherical analyzer
o 128-channel detector
· X-ray source
o Al Kα micro-focused monochromator
o Variable spot size (30-400µm in 5µm steps)
· Ion Gun
o Energy range 100-4000eV
· Charge Compensation
o Dual beam source
o Ultra-low energy electron beam
· Sample Handling
o 4-axis Sample Stage
o 60 x 60mm sample area
o 20mm maximum sample thickness
· Vacuum System
o 2x 260 l/s turbo molecular pumps for entry & analysis chambers
o Auto-firing, 3 filament TSP
· Data system
o Avantage data system
o Processing license
o PC
K-Alpha XPS Analysis from Research to Routine
· High Performance Spectroscopy
o Source-defined analysis area from 30-400 μm
o 5 μm step size ensures that the analysis area closely matches the feature to be analyzed
o Rapid survey spectrum acquisition
o Excellent energy resolution for chemical state determination
· Chemical State Imaging XPS
o Spectral Imaging
o Rapid 128 channel snapshot spectra
o Entire sample stage area imaging
o Overlay XPS data with automatically collected optical images
· Insulator Analysis
o Insulating samples are easily analyzed using state-of-the-art charge compensation
o Simple one-click turnkey operation
· Depth Profiling
o Ion gun provides high current density even at low beam energy
o Azimuthal and Comp-eucentric rotation
o Full computer control of the ion gun and gas handling for excellent reproducibility
o Automatic alignment of source
AvantageTM Data System
The AvantageTM data system incorporates a comprehensive suite of software for:
• Total instrument control
• Data acquisition
o Spectra
o Images
o Profiles
o Linescans
• Data interpretation
o Auto elemental and chemical state ID
• Data processing
o Quantification, peak fitting, real-time profile display, spectrum-image manipulation
• Advanced processing
o PCA, Phase analysis, TFA, NLLSF, PSF removal
o Optical/XPS image overlays
• Report generation
• Vacuum system and sample handling
