Structural Properties of VOTTDPz Investigated by means of STM
Author
Nielsen, Simon Emil
Term
4. term
Education
Publication year
2020
Submitted on
2020-12-13
Abstract
Denne afhandling undersøger, ved hjælp af scanning-tunnelmikroskopi (STM) og scanning-tunnelspektroskopi (STS), de strukturelle egenskaber af vanadyl tetrakis(thiadiazole) porphyrazin (VOTTDPz), et metal-organisk molekyle beslægtet med phthalocyaniner. Målet er at klarlægge, hvordan molekylet selv-samler og orienterer sig på de noble metalsubstrater Ag(111) og Au(111), og hvordan dækningsgrad og efterfølgende annealering påvirker de observerede strukturer og de lokale elektroniske egenskaber. Arbejdet omfatter fremstilling under ultrahøjvakuum, grundig rengøring af substrater, kontrolleret deponering og efterbehandling, samt systematisk afprøvning af billedkontrast som funktion af bias og tunnelforestilling for at koble topografi og elektronisk struktur. Som supplement er VOTTDPz karakteriseret ved pulverrøntgendiffraktion (PXRD), elektronparamagnetisk resonans (EPR) og bulk magnetiske målinger i samarbejde med Københavns Universitet for at belyse kemiske og magnetiske egenskaber. Baggrundskapitlerne gennemgår selv-samling og balance mellem molekyle–molekyle- og molekyle–substrat-interaktioner samt relevant tunnelerings- og overfladeteori for Ag(111)/Au(111). Uddraget indeholder ikke specifikke, kvantitative fund, men afhandlingen tilvejebringer et sammenlignende datasæt for VOTTDPz på Ag(111) og Au(111) som funktion af dækningsgrad og behandling, med henblik på at informere kontrol af struktur, elektronisk kobling og potentielt magnetisk adfærd i fremtidige nano- og spintroniske anvendelser.
This thesis uses scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) to investigate the structural properties of vanadyl tetrakis(thiadiazole) porphyrazine (VOTTDPz), a metal–organic molecule related to the phthalocyanine family. The central objective is to understand how VOTTDPz self-assembles and orients on noble metal surfaces Ag(111) and Au(111), and how molecular coverage and post-deposition annealing influence the resulting structures and local electronic characteristics. The work comprises ultrahigh-vacuum preparation, thorough substrate cleaning, controlled deposition and annealing, and systematic assessment of imaging contrast versus bias and tunneling setpoint to relate topography to electronic structure. Complementary characterization by powder X-ray diffraction (PXRD), electron paramagnetic resonance (EPR), and bulk magnetic measurements was carried out with the University of Copenhagen to probe chemical and magnetic properties. Background chapters review self-assembly and the balance of molecule–molecule and molecule–substrate interactions, as well as tunneling theory and surface states relevant to Ag(111)/Au(111). The excerpt does not provide specific, quantitative findings, but the thesis delivers a comparative data set for VOTTDPz on Ag(111) and Au(111) as a function of coverage and treatment, aiming to inform control of structure, electronic coupling, and potentially magnetic behavior for future nanoelectronic and spintronic applications.
[This summary has been generated with the help of AI directly from the project (PDF)]
Documents