Electronic and chemical structure of the H2O/GaN(0001) interface under ambient conditions

Abstract

We employed ambient pressure X-ray photoelectron spectroscopy to investigate the electronic and chemical properties of the H2O/GaN(0001) interface under elevated pressures and/or temperatures. A pristine GaN(0001) surface exhibited upward band bending, which was partially flattened when exposed to H2O at room temperature. However, the GaN surface work function was slightly reduced due to the adsorption of molecular H2O and its dissociation products. At elevated temperatures, a negative charge generated on the surface by a vigorous H2O/GaN interfacial chemistry induced an increase in both the surface work function and upward band bending. We tracked the dissociative adsorption of H2O onto the GaN(0001) surface by recording the core-level photoemission spectra and obtained the electronic and chemical properties at the H2O/GaN interface under operando conditions. Our results suggest a strong correlation between the electronic and chemical properties of the material surface, and we expect that their evolutions lead to significantly different properties at the electrolyte/electrode interface in a photoelectrochemical solar cell.

The Influence of Ga–OH Bond at Initial GaN Surface on the Electrical Characteristics of SiO2/GaN Interface

“…To separate the peaks in the O1s spectrum, we separately fitted the Ga–O component, the Ga–OH‐related components, and the H 2 O‐related components (Figure ). The binding energies of these three components were 530.3, 531.4, and 532.6 eV, respectively, similar to those in a recent report . The peak separation (1.1 eV) between Ga–O and Ga–OH was also consistent with that of previous reports (0.6–1.5 eV) .…”

“…The binding energies of these three components were 530.3, 531.4, and 532.6 eV, respectively, similar to those in a recent report . The peak separation (1.1 eV) between Ga–O and Ga–OH was also consistent with that of previous reports (0.6–1.5 eV) . For the peak separation analysis, the O1s XPS spectra of the wet‐annealed and wet‐cleaned samples were calibrated by the energy‐band offset observed in the Ga2p spectrum.…”

“…First, the chemical bonding of each GaN surface was evaluated by X‐ray photoelectron spectroscopy (XPS). Reports on Ga–OH have gradually accumulated, but the binding energies of the XPS peak separation are inconsistent among the studies. In our XPS measurements, we evaluated the Ga2p, N1s, and O1s spectra.…”

What Limits the Performance of Ta3N5 for Solar Water Splitting?

“…The understanding is consistent with a recent study on the surface of GaN on reactions with H 2 O. 42…”

Effect of surface passivation process for AlGaN/GaN HEMT heterostructures using phenol functionalized-porphyrin based organic molecules

“…Considering the elements constituting the top layer, AlGaN, Al 2p scan was fitted by two subpeaks [ Fig. 2(a)] which represent Al-N (subpeak 1: 73.69 ± 0.016 eV) 39 39 bonds, N-Ga (subpeak 8: 397.96 ± 0.02 eV) 42 bonds, N element in N-tetraphenylporphyrin (subpeak 7: 397.37 ± 0.011 eV) 44 (constituent of MoL), and Auger peaks of Ga (subpeak 9: 395.87 ± 0.029 eV and subpeak 10: 394.62 ± 0.029 eV) 45 element. These curve fittings confirmed the presence of MoL of porphyrin based organic molecules on the sample surface.…”