Bias-voltage application in a hard x-ray photoelectron spectroscopic study of the interface states at oxide/Si(100) interfaces

Abstract

The energy distribution of the interface states in the Si band-gap at an ultrathin oxide/Si(100) interface was investigated using a bias-voltage application in hard x-ray photoelectron spectroscopy. For the SiO2/Si interface, interface states were observed near the mid-gap, whereas the interface states for the SiON/Si interface increased around the mid-gap and new states formed near the conduction band minimum (CBM) and valence band maximum (VBM) compared to the case of the SiO2/Si interface. Moreover, the interface state density increased with the nitrogen concentration in the oxide, but the spectral shape was independent of the nitrogen concentration. The N1s spectra indicated that the N−O species at the SiON/Si interface induced inhomogeneous interface sites. Because inhomogeneity might break or weaken bonds at the SiON/Si interface, the density of broken bonds (the mid-gap states) and weakened bonds (the states near VBM and CBM) at the interface increased as the number of inhomogeneous sites increased.

In Situ Tuning of Magnetization and Magnetoresistance in Fe3O4 Thin Film Achieved with All-Solid-State Redox Device

“…In situ hard X-ray photoelectron spectroscopy (HX-PES) was performed at the undulator beamline BL15XU of SPring-8 to examine the valence modulation of the Fe ions during device operation. − The Fe 2s core-level spectra of the Fe 3 O 4 thin film were observed under various applied DC voltage conditions (see Methods and section S4 for experimental details). The HX-PES spectra were calibrated using Pt 4f peaks of the top Pt film which is very stable for electrochemical reaction and thus can be reliable reference.…”

“…The overall resolution of the instrument estimated is 0.15 at 5948 eV of photon energy, while the binding energy values are referenced to the metallic Au Fermi edge. The present measurements were performed using the excitation by hard X-ray source at an incident angle of 82°, which can penetrate to micrometer range, and the detection of photoelectron with an escape depth of 10–20 nm. − All HX-PES measurements were conducted in a high vacuum, typically 7.0 × 10 –8 Pa.…”

Formation of an interphase layer during deposition of cobalt onto tetraphenylporphyrin: a hard X-ray photoelectron spectroscopy (HAXPES) study

“…In recent related work, the characterization of the electronic states in buried layers using bias voltage dependent HAXPES has been proposed. 41,42 By analyzing the HAXPES data taken with changing detection angles, Shibuta et al have unveiled the depth profile of specific chemical states at the buried hetero-interface of organic/organic (CuPc/C 60 ) and metal/organic (Au/C 60 ) systems. 43 In our study, we take advantage of chemical depth profiling with HAXPES to investigate the model system Co/2HTPP.…”

Hybrid Materials with Antimicrobial Properties Based on Hyperbranched Polyaminopropylalkoxysiloxanes Embedded with Ag Nanoparticles

“…This charge shifts the photoelectron peaks towards higher binding energies. Regions with different secondary electron emission coefficients (γ), work functions (φ) and conductive properties (ρ) are charged differently, which causes broadening and shift of the observed photoelectron spectra [ 50 , 51 , 52 , 53 , 54 ]. This phenomenon, which characterizes the inhomogeneity of the surface, is called differential charging.…”