Structural and XPS characterization of ALD Al2O3 coated porous silicon

•ALD Al2O3 thin films grown on porous silicon surface have been investigated.•Morphology and chemical composition of the deposited Al2O3 films were established.•The band gap energies of Al2O3 coated porous silicon were estimated.

Al2O3 thin films were grown on highly-doped p-Si (100) macro- and mesoporous structures by atomic layer deposition (ALD) using trimethylaluminum (TMA) and water H2O as precursors at 300 °C. The porous silicon (PSi) samples were fabricated utilizing a metal-assisted chemical etching process (MACE). The morphology of the deposited films and initial silicon nanostructures were investigated by means of scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX). X-ray photoelectron spectroscopy (XPS) was used to analyze the chemical elemental composition by observing the behavior of the Al 2p, O 1s and C 1s lines. Calculated Auger parameter and binding energy analysis confirmed Al2O3 formation. The measurement of band gap energies of Al2O3 was performed.