What Is a Glow Discharge Optical Emission Spectroscopy (GDOES)
GDOES is a technique for elemental compositional analysis and depth profiling of solids. It is particularly well suited for analysis on thin‑ and thick‑film samples, or for depth‑profiling of multilayer film stacks.
The advantages of GDOES are short analysis times with minimal sample prep, the ability to measure a wide range of elements simultaneously (including C/H/N/O), fast depth profiling, and the ability to analyze surface and bulk composition in a single measurement.
High Depth Resolution
Wide Element Range
Fast Multi-Element Profiling
Why Use GDOES?
Glow Discharge Optical Emission Spectroscopy (GDOES) is a fast, quantitative technique for elemental composition and depth profiling of solid materials. It enables simultaneous detection of all elements, including light ones like H, C, N, O, and Li—with minimal sample preparation.
GD-OES is ideal for studying thin films, multilayers, and coatings across metals, semiconductors, and ceramics, providing rapid, high-resolution insights that support R&D, quality control, and failure analysis.
Rapid Layer Insight
Minimal Sample Prep
Broad Material Compatibility
How GDOES Works
In a GDOES measurement, a low‑pressure glow‑discharge (GD) plasma (typically Argon) is used to sputter away the surface of the sample being measured. As material is sputtered from the surface, the high‑energy plasma induces subsequent fluorescence events characteristic of the elements in the plasma. These photons are detected by an optical emission spectrometer (OES).
The intensity (for a given emission line) is proportional to element concentration in the ionizing plasma. Time can be correlated to depth from a sample’s surface, enabling depth profiling and quantitative compositional analysis.
Equipment Used for GDOES
Covalent’s GDOES capability is powered by the GD-Profiler 2 pulsed RF Glow Discharge Optical Emission Spectrometer, enhanced with Differential Interferometry Profiling (DiP). This system delivers ultra-fast, high-resolution depth profiling across thin and thick coatings, with nanometer-scale precision in erosion depth measurement. It supports all elements from trace to bulk, handles both conducting and insulating materials, and includes advanced optical detection for high dynamic range and simultaneous multi-element analysis, which is ideal for multilayers, interfaces, and bulk composition studies.
Horiba Profiler 2 Pulsed-RF Glow Discharge Optical Emission Spectrometer
- Spectral Range: 120 nm to 800 nm.
- Simultaneous measurement: Of all elements, including light elements H, C, N, O, F, L.
- Spot Size: 2 to 8 mm.
- Depth resolution: As low as ~1 nm.
- High Dynamic Detector with industry-leading integration times and linear dynamic acquisition range (5 x 109).
- Plasma Sputtering Ion Energy: 50eV.
- Pulsed Plasma Gas Ion Frequency: 13.56 MHz RF.
- Anode Tube Diameter: 4mm.
Key Differentiators
GDOES vs XPS vs Dynamic SIMS Depth Profiling
| GDOES | XPS | Dynamic SIMS | |
|---|---|---|---|
| Speed | Minutes per profile | Slow (etch-and-measure cycles) | Slow |
| Depth range | Nanometers to ~100 µm | Top ~10 nm, deeper with ion etching | Nanometers to microns |
| Sensitivity | ppm to wt% | ~0.01–0.5 at% | Highest (trace dopants) |
| Analysis area | 2–8 mm spot | 10–400 µm spot | Small area |
| Best for | Thick coatings, platings, multilayers, fast QC | Surface chemistry and chemical states | Dopants and trace impurities |
Strengths
- Wide dynamic range (ppm to wt%).
- Full periodic table.
- Excellent depth resolution (nm-scale).
- Fast depth profiling.
- Minimal sample prep.
- Great for quickly profiling complex layered materials.
Limitations
- Less sensitive than GD-MS.
- Elemental concentration and depth scales both need external calibration.
- High-energy sputtering may cause diffusion of light elements, limiting accuracy.
Example Outputs
The depth profile of a CuInGaSe Solar Cell shows how GDOES can be used to extract quantitative compositional information as a function of penetration depth into a sample after some additional analytical steps are performed (as described in this application note). From: Horiba
Depth profile of Na2O and K2o in ion exchanged chemically strengthened glass.
Sample Requirements
- Solid, flat, smooth, or rigid materials.
- Conductive materials are preferred for optimal performance.
- Insulating materials can be analyzed, but may pose additional challenges.
GDOES Applications by Industry
Metallurgy
Verify the composition of alloys and measure the thickness of oxides or coatings, supporting routine quality control operations.
Photovoltaics
Determine the thickness and chemical composition of multilayered materials and assess interface quality and interdiffusion.
Energy & Battery Manufacturing
Use depth profiling of electrodes to assess the depth of lithiation.
Consumer Electronics
Identify and quantify impurities in specific regions or layers of printed circuit boards (PCBs).
Aerospace & Composites
Determine the thickness and chemical composition of coatings.
Techniques That Complement GDOES
GD-MS offers better sensitivity than GDOES for most elements, down to trace levels, but is generally limited to bulk analysis rather than depth profiling.
Quantifies multiple elements at very low concentrations.
GDOES Testing Services at Covalent
GDOES runs in our Sunnyvale Core Lab on a Horiba GD-Profiler 2 with Differential Interferometry Profiling (DiP), which measures crater depth directly for accurate depth scales. We handle conductive and insulating samples, offer air-free transfer for sensitive materials, and correlate results with XPS, SEM-EDS, and other in-house techniques.
Frequently Asked Questions
What types of materials can be tested with GDOES?
What information does GDOES provide?
How deep can GDOES be analyzed in a material?
Why use GDOES instead of another surface analysis technique?
GDOES provides much faster depth profiling than other techniques like SIMS or XPS. It also has the advantage of capturing light elements like H and Li.