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Starfelt, Samuel
Publications (2 of 2) Show all publications
Starfelt, S., Johansson, L. & Zhang, H. (2020). Initial quantum well states in Ag thin films on the In/Si(111)-root 3 x root 3 surface. Surface Science, 692, Article ID 121531.
Open this publication in new window or tab >>Initial quantum well states in Ag thin films on the In/Si(111)-root 3 x root 3 surface
2020 (English)In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 692, article id 121531Article in journal (Refereed) Published
Abstract [en]

Silver thin films have been formed by room temperature deposition of Ag on In/Si(111)-root 3 x root 3. The Ag films have been investigated using both angle-resolved photoelectron spectroscopy (ARPES) and scanning tunneling microscopy and spectroscopy (STM/STS). This creates a powerful link between the electronic structures and the film morphology. The valence band spectra show a clear evidence of quantum well state (QWS) formation already for a 2 monolayer (ML) film. This QWS moves towards the Fermi level for the 3 ML film, which also reveals a second QWS. The QWSs' dispersions have been plotted along the (Gamma) over bar(M) over bar and (Gamma) over bar(K) over bar symmetry lines of the 1 x 1 surface Brillouin zone (SBZ), where the (Gamma) over bar(M) over bar direction shows the umklapp-mediated QWSs. The valence band spectra for the 3 ML Ag film also show a strong Ag sp band close to the edge of the Ag(111) 1 x 1 SBZ. In the STS spectrum from 2 ML, two peaks are visible below the Shockley surface state. These peaks are compared with the ARPES data and attributed to different features of the QWS, namely the turning part where the QWS band intersects with the bulk Si valence band region and the local binding energy minimum close to the (Gamma) over bar point.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Quantum well states, Thin films, Semiconductor, ARPES, STM/STS
National Category
Physical Sciences
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-76235 (URN)10.1016/j.susc.2019.121531 (DOI)000502892900008 ()
Available from: 2020-01-09 Created: 2020-01-09 Last updated: 2020-03-12Bibliographically approved
Starfelt, S., Zhang, H. & Johansson, L. (2018). Quantum-well states in thin Ag films grown on the Ga/Si(111)-root 3 x root 3 surface. Physical Review B, 97(19), Article ID 195430.
Open this publication in new window or tab >>Quantum-well states in thin Ag films grown on the Ga/Si(111)-root 3 x root 3 surface
2018 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 97, no 19, article id 195430Article in journal (Refereed) Published
Abstract [en]

Silver thin films have been created by room temperature deposition on a Ga/Si(111)-root 3 x root 3 surface and their valence band structures and core levels have been measured by angle-resolved photoelectron spectroscopy (ARPES). Discrete quantum-well states (QWSs) quantized from the Ag sp valence band are observed already at 3 monolayers (ML). The characteristics of the QWSs have been examined in the phase accumulation model for thicknesses between 3 and 12 ML. The phase shift and QWSs binding energies dependence with Ag film thicknesses have all been consistently derived. In-plane energy dispersion follows a parabolic curve, and the effective mass of the QWSs shows an increasing trend with binding energies as well as with reduced film thicknesses. Furthermore, the ARPES measurements reveal umldapp mediated QWSs around the (M)over-bar points of the Si(111) 1 x 1 surface Brillouin zone. The study confirms that the Ga/Si(111)-root 3 x root 3 surface is a good substrate for growing uniform ultrathin Ag films in room temperature conditions.

Place, publisher, year, edition, pages
American Physical Society, 2018
National Category
Condensed Matter Physics
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-67486 (URN)10.1103/PhysRevB.97.195430 (DOI)000433009300010 ()
Available from: 2018-06-07 Created: 2018-06-07 Last updated: 2018-07-24Bibliographically approved
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