Growing oxide thin films in a low-energy electron microscope

Author(s):
Torren, A.J.H. van der
Published
2016
Publication type
Doctoral Thesis

Abstract

By combining low-energy electron microscopy (LEEM) with pulsed laser deposition (PLD), we have created a unique set-up to study the first stages of growth of complex metal oxides. We demonstrate this by investigating the growth of SrTiO3 (STO) and LaAlO3 (LAO) on STO in real-time.

We follow growth by monitoring the intensity and the full-width-half-maximum (FWHM) of the specular diffracted beam at various energies. For layer-by-layer growth, we find the anticipated intensity peaks at the completion of each layer, and an oscillatory FWHM with the maximum at half-layer coverage.

In the LAO on STO case, for optimal growth conditions and a LAO thickness above the critical thickness of 4 unit cells the interface between the band insulators shows conductivity. We obtain an electronic fingerprint of the growing material, by measuring the intensity of the specular beam as a function of energy at regular intervals during growth. Extending this fingerprint with the intensity dependence on the momentum parallel to the surface allows us to extract the band dispersion of unoccupied electron states of the sample surface. Significant differences in the unoccupied band structure develop between samples which are conducting and non-conducting.

Low-energy electron microscopyLEEMPusled laser depositionPLDLaAlO3SrTiO3
Defense date
2016-12-05
Language
English
Supervisor(s)
Aarts, J.
Advisor(s)
Molen, S.J. van der
Committee member(s)
Dittmann, R.; Rijnders, A.J.H.M.; Caviglia, A.; Eliel, E.R.; Oosterkamp, T.H.
Qualification
Ph.D.
Degree granting institution
Leiden Institute of Physics (LION), Science, Leiden University, Leiden
hdl
1887/44732
ISBN(s)
9789085932765
Series
Casimir PhD Series
Volume in series
2016-32

Funding

Sponsorship
The work described in this thesis is supported by the Netherlands Organisation for Scientific Research (NWO) by means of a ”NWO Groot” grant and by the Leiden-Delft Consortium NanoFront. The work is part of the research programmes NWOnano and DESCO, administered by the Foundation for Fundamental Research on Matter (FOM), which is part of NWO.