Demonstracijski poskusi s tunelskim mikroskopom v zraku

Starc, Mitja (author), Golli, Bojan (mentor), Bavdek, Gregor (co-mentor)

Za razumevanje delovanja tunelskega mikroskopa sem opisal nekatere zakonitosti kvantne mehanike. Predstavil sem pojav tuneliranja delcev, ki je pomemben proces pri delovanju tunelskega mikroskopa. Meritve s tunelskim mikroskopom se običajno izvajajo v ultra visokem vakuumu, ker se vzorci sicer hitro onesnažijo. Ker poskušam poskuse s tunelskim mikroskopom umestiti v pouk, sem se osredotočil na tunelsko mikroskopijo v zraku, ki je dostopna z nižjimi stroški, vendar ima svoje omejitve. Tlak okoliškega plina vpliva na nabiranje nečistoč na vzorcu in igli. Za izvajanje meritev tunelske mikroskopije v zraku potrebujemo vzorce, ki se ne onesnažijo hitro. Predstavil sem nekaj značilnih poskusov na takih vzorcih in na nekaterih izvajal tudi lastne meritve ter dosegel atomsko ločljivost. Na vzorcih orientiranega grafita (HOPG), čistem vzorcu zlata Au(111) in na vzorcu zlata z grafenskimi nanotrakovi GNR/Au(111) sem meritve izvajal z iglami iz volframa (W) in zlitine platine in iridija (Pt/Ir). Na zajetih slikah vzorca HOPG sem videl vzorce, ki predstavljajo posamezne atome ogljika, in terase med plastmi ogljikovih atomov. Določil sem razdalje med plastmi in analiziral fragmente na površini. Na vzorcu zlata Au(111) sem opazil stopnice med plastmi atomov zlata, na eni od zajetih slik pa videl tudi vzorec urejenih atomov. Na vzorcu zlata z grafenskimi nanotrakovi GNR/Au(111) so bile najverjetneje prisotne nečistoče, ki so mi onemogočale natančne meritve.

• Language: Slovenian
• Keywords: tunelski mikroskop v zraku
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: PEF - Faculty of Education
• Year: 2016
• PID: 20.500.12556/RUL-86032
• COBISS.SI-ID: 11210569
• Publication date in RUL: 19.09.2017

Secondary language

• Language: English
• Title: Demonstration experiments with scanning tunneling microscope in air

Abstract

To understand the functioning of the scanning tunneling microscope I describe some basics of quantum mechanics. I present the process of particle tunneling. Measurements with scanning tunneling microscope are usually done in ultra high vacuum, otherwise samples get quickly contaminated. My aim is to incorporate experiments with scanning tunneling microscope into educational process, so I have focused on scanning tunneling microscopy in air which is cheaper, but has some restrictions. Air pressure is a factor we cannot ignore when talking about sample and tip contamination. For measurements in air we need samples that stay clean for long enough so I present samples adequate for measurements at ambient conditions. I describe known experiments on such samples. The thesis also contains my own mesurements on oriented graphite (HOPG), gold Au(111) and gold with graphene nanoribbons GNR/Au(111) with tungsten (W) and platinum/iridium (Pt/Ir) tips. I have reached atomic resolution on HOPG and I have also seen steps on Au(111). The GNR/Au(111) sample has probably been contaminated which has prevented acurate measurements.

• Keywords: scanning tunneling microscope in air