Scanning Tunneling Microscopy/Spectroscopy Measurements And Density Functional Theory Calculations On Cr/Si Modified Surfaces And Probing Dielectric Properties Of A Si Nanocrystal Thin Film Using XPS
Date of Award
Doctor of Philosophy (PhD)
Physics & Astrophysics
CrSi2 is an important refractory metal-silicide with high thermal power and a narrow bandgap which makes it a suitable material for high-temperature thermoelectric applications. The present work investigates the early stages of the growth of Cr film on Si (110) and its electronic properties by combining Scanning Tunneling Microscopy and Density Functional Theory. Cr atoms deposited on Si (110) formed grains of CrSi2 with interfacial dislocations along 1/2<1 1-1> Burgers vectors. After annealing at 1100°C, disconnected CrSi2 crystallites emerged. The crystallites had well-defined facets. Scanning tunneling spectroscopy measurements showed that the crystallites were metallic. Simulated DOS data of the facets also confirmed the metallic nature of the crystallites. We performed X-ray photoelectron spectroscopy (XPS) measurement on a thin film of Si nanocrystals (SiNCs) while applying a DC or an AC external bias to calculate its resistance and capacitance. The measurement consists of the application of 10 V DC and square wave pulses of 10 V amplitude to the sample at various frequencies ranging from 0.01 Hz to 1 MHz while recording X-ray photoemission data. To analyze the data, we propose three different models with varying degrees of accuracy. The calculated resistance and capacitance values agree with each other and the data published in the literature within the accuracy of the calculations.
Pathiranage, Sameera Madhusanka Pathirana, "Scanning Tunneling Microscopy/Spectroscopy Measurements And Density Functional Theory Calculations On Cr/Si Modified Surfaces And Probing Dielectric Properties Of A Si Nanocrystal Thin Film Using XPS" (2022). Theses and Dissertations. 4368.
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