Dependence of high density polyethylene XPS spectrum on electron flood gun parameters

Abstract

As specimen charging appears the most significant obstacle in x-ray photoelectron spectroscopy (XPS) analysis of insulators, the application of low energy flood gun was investigated. Dependence of silicon 2s peak properties (position and full width at half maximum), on electron flood gun parameters (emission current and accelerating voltage), was observed. In the first stage of the experiment, flood gun accelerating voltage was kept constant at 2 V, and emission current varied from 2 μA to 50 μA. Peak's position shifted towards lower energy values with increase of emission current, reaching referent value for emission current of 50 μA. Full width at half maximum (FWHM) of Si2s peak increased with increase of emission current. In the second stage of the experiment, emission current was kept constant at 2 μA, and accelerating voltage varied from 1.5 V to 3 V. Peak's position shifted towards lower energy values with increase of accelerating voltage, reaching referent value for accelerating voltage of 3 V. FWHM of Si2s peak increased with increase of accelerating voltage. By changing flood gun emission current and accelerating voltage, it is possible to achieve predictable shifts of peaks' positions, and obtain accurate spectrum.

Keywords

• XPS spectrum
• charging
• neutralization
• electron flood gun
• peak's position