Electrochemical preparation of a stable accumulation layer on Si: A synchrotron radiation photoelectron spectroscopy study

Abstract

Chronoamperometric conditioning of float zone n-Si(111) in 2M NaOH solution in the potential range negative from open-circuit potential is performed in a combined electrochemistry/ultrahigh-vacuum surface analysis experiment. Synchrotron Radiation Photoelectron Spectroscopy measurements at the U49/2 beamline at Bessy II using the SoLiAs facility show formation of a ultrahigh-vacuum-stable permanent accumulation layer without junction formation. Comparison of the Thomas–Fermi screening potential and the mean inelastic scattering length λesc of photoelectrons at hν=150eV (λesc=4Å) and hν=585eV (λesc=15Å) indicates a surface electron concentration of 3×1018cm−3 for a bulk doping level of 1015cm−3. The observed shift of the Si2p3∕2 and 2p1∕2 core level with photon energy is in excellent agreement with the shifted onset of the x-ray photoelectron spectroscopy valence-band spectrum measured at hν=150eV.

Enzyme–semiconductor interactions: Routes from fundamental aspects to photoactive devices

“…The atomic bilayer (BL) height on the (111) surface is 0.314 nm; hence these steps have heights of about 16BL-36BL. In synchrotron radiation photoelectron spectroscopy (SRPES) it was shown that these surfaces are in an accumulation condition where the Fermi level is located only 0.06 eV below the conduction band edge whereas from the bulk doping, this energetic difference amounts to 0.26 eV [29]. In separate Kelvin probe AFM measurements, it has been found that the negative charge associated with the accumulation condition is located at the step edges of the nanostructure [35] as schematically indicated in Fig.…”

“…The former is obtained by CVT (chemical vapour transport) growth [27] and the latter is prepared from H-terminated Si(111) in alkaline solutions either chemically or electrochemically [28,29]. Figure 2 shows the basic atomic structure of the group VI transition metal dichalcogenide layered semiconductor MoTe 2 .…”

Operational principles of electrochemical nanoemitter solar cells for photovoltaic and photoelectrocatalytic applications

“…Electrodeposition of Pt from PtCl 2À 6 complexes onto n-Si yielded different sizes for H-terminated (1 1 1) surfaces and for the step bunched Si surface where the major terraces are (1 1 1) oriented and the bunched steps are likely to show (1 1 0) orientation [19,20]. At step bunched surfaces, the Pt NPs had an average width of 30 nm and a height of 3 nm.…”

Fundamental Aspects of Electrodeposition for the Realization of Plasmonic Nanostructures

“…Synchrotron radiation photoelectron spectroscopy (SRPES) performed on this type of surfaces allows one to establish the valence band onset at 1.06 eV. [37] This distance between the valence band and the Fermi level indicates that the preparation at negative potentials in alkaline solution where strong hydrogen evolution occurs results in the n-type doping effect discussed above. This has been derived from the energetic difference Fermi level to valence band onset with respect to the flat band situation at~0.8 eV.…”