Raw data
TXT exports straight from the spectrometer software. One or many spectra per file, any number of files, 1800 or 600 gr/mm.
Results
Click a row to see that spectrum's plot. Tick the boxes to stack several spectra for comparison.
| Pick | File · # | Δ (cm⁻¹) | Si raw | Shift | E¹₂g | A₁g |
|---|
How it works
Each spectrum is shifted so its own Si peak sits at the reference, then E¹₂g and A₁g are located between data points by a Gaussian fit through each peak top. Their difference sorts every spot into a layer class.
Si calibration
The Si peak (490 to 555 cm⁻¹) gets a straight baseline, then a Gaussian fit through its top gives the position between data points. A flat, saturated top is located from the midpoint of its two sides at 75% height. The whole spectrum is shifted so Si lands on the reference.
MoS₂ peaks
On the shifted axis, E¹₂g (372 to 394) and A₁g (396 to 418) are found the same way, with widths read at half height. The peak difference is A₁g minus E¹₂g; the Si shift moves both peaks equally, so it never changes the difference.
Accuracy
A spectrum counts as MoS₂ when A₁g is more than 6 times the noise. On coarse 600 gr/mm scans the difference is good to about ±0.5 cm⁻¹. Values within 0.3 of a class boundary are borderline.